A London rent-vs-buy scenario pack that keeps childcare years and compounding in view — in today’s pounds.
Picture a misty Sunday in Walthamstow: two 32-year-old professionals eye a pushchair in the hallway, a Zone 3 rent review on the table, and a summer 2029 target to pull together a first-home deposit - likely just after a baby arrives in early 2029. Between them they net roughly £4.7k–£6.7k/month after PAYE, NI, and 5% workplace pensions. But any family-ready flat already rents for £1.9k–£2.8k/month in today’s money, and nursery quotes come in around £1,400/month.
This scenario pack compares two very human choices: keep renting (and keep more money compounding), or buy by 35 (and accept a tight liquid buffer right when childcare peaks).
All currency figures are shown in today’s pounds, so inflation is already stripped out. Each path is tested in lower, middle, and stronger market conditions so you can see how much the outcome depends on compounding.
Age & timeline: 32 today, target retirement at 68, plan horizon to age 90.
Location: Greater London renters looking to stay in Zone 3 once a baby arrives.
Household income: £4.7k–£6.7k/month take-home (after PAYE/NI and 5% employee pension).
Current savings: £50k cash buffer before any deposit withdrawals.
Savings effort: Renting asks for less monthly investing effort than buying because the buy path needs more cash up front and carries somewhat higher housing costs.
Savings path (shape): Before children arrive, the household saves aggressively. That effort drops materially during the nursery years, then rebuilds through the 40s and 50s once childcare eases.
Housing & family costs: Expect a more expensive family-sized rental or somewhat higher ownership costs than current rent, a steep nursery-cost hump in the early years, and smaller child costs later on.
Buying costs (buy track): The buy path needs a six-figure deposit, meaningful buying fees, some post-purchase work, and later repair reserves. It also assumes family help at purchase so the cash buffer does not turn negative during the deposit window.
Other planned goals: The scenario also makes room for car replacements, education support, milestone travel, later-life care, and normal family/lifestyle spending before retirement.
Retirement target: The rent path aims for a somewhat higher retirement lifestyle and a planned housing gift for an adult child. In the lower-return rent case, that target has to tighten. The buy path starts from a slightly leaner investable-asset spending baseline, with home equity treated as a separate decision.
At a glance: In the rent track, the base case finishes with ≈£117K liquid at age 90 and the stronger-return case with ≈£634K. The lower-return rent case still stays positive, but only after tightening later-life spending.
In the buy track, family help at purchase keeps the household solvent through the deposit window. On investable assets alone (home equity not counted), the pack finishes with ≈£440K liquid at age 90 in the base case, ≈£224K in the lower-return case, and ≈£273K in the stronger-return case because that version also carries extra late-life family/care spending. Buffer-safe retirement spending lands in the ≈£2,605-£3,973/month range depending on case (≈£3,087/month in the base case without tapping home equity).
Renting keeps more capital compounding for longer, so interest earned by retirement ranges from ≈£216K in the lower-return case to ≈£471K in the stronger-return case.
Buying by 35 ties up a six-figure upfront housing bill right as childcare peaks, so interest earned by retirement is ≈£140K-£297K across the buy cases.
How to read this: Effort/mo is the average monthly amount you’re investing during your working years (separate from workplace pension contributions). Safe is the estimated retirement spending level that keeps a 60‑month buffer in the projection - use it as a planning guardrail, not a promise.
Path
Market case
Effort/mo
Safe retirement spend
Liquid at age 90
Rent forever
Base case
£2,036
£3,781
≈£117K
Rent forever
Lower-return case
£2,036
£3,087
≈£57K
Rent forever
Stronger-return case
£2,036
£5,105
≈£634K
Buy by 35
Base case
£2,454
£3,087
≈£440K
Buy by 35
Lower-return case
£2,454
£2,605
≈£224K
Buy by 35
Stronger-return case
£2,454
£3,973
≈£273K
Renting (base case): Close to the higher lifestyle target, but you’re budgeting above the “safe” guardrail (so you’d want either a bit less spending, a bit more saving later, or a bigger buffer).
Renting (lower-return case): With weaker markets, the higher lifestyle target stops working unless you reduce spending (or raise saving) later.
Renting (stronger-return case): If markets are that kind, the extra cushion is where you’d fund late-life care, family support, bigger travel, or simply choose more spending earlier - it’s not a guaranteed leftover; the run ends with ≈£634K (roughly 13 years of spending), so plan specific uses or raise retirement spending rather than assuming it’s idle cash.
Buying: You need slightly higher saving effort, but the bigger story is the upfront housing bill right as childcare begins; on investable assets alone, retirement spending is tighter unless you plan to unlock home equity later.
“Safe” = the retirement spending level that keeps a 60‑month buffer in the projection (use it as a planning guardrail, not a guarantee).
A quick fairness note: these rent runs are not the “maximise wealth” version of renting. They include a planned housing gift for an adult child plus later-life accessibility/care spending, so the larger balances already have jobs to do.
Capital and interest figures report investable assets only, in today's pounds. Home equity stays offstage unless you add a future sale or downsizing step, so plan to monetise the property if you need that value later.
Average saving effort rises by just ≈£400/month in the buy path. The bigger difference is when the cash leaves your account: tying up a six-figure housing sum early can mute compounding. In the base case, the rent-first plan compounds to about £306K of interest by retirement (and ≈£580K across the full horizon) versus about £197K by retirement (and ≈£584K across the full horizon) in the buy runs, despite their higher monthly effort and the assumed family help at purchase.
The rent track starts with a £50K cash buffer and avoids a six-figure deposit drain. You still pay the normal one-offs (move, baby prep, car) from your liquid pot, so the buffer can dip during expensive months.
The shape is:
Age 34: move to a larger rental before the baby arrives.
Childcare years: nursery costs are heaviest in the first few years, then ease once funded hours kick in.
After childcare: child costs continue as smaller monthly lines, alongside ordinary family activities and lifestyle upgrades.
Saving effort over time: saving dips into the low four figures while rent and nursery overlap, then rebuilds materially in the 40s and 50s.
Because no deposit leaves the account, the base case earns ≈£306K of interest by retirement (and ≈£580K across the full horizon). In the lower-return run, the original retirement lifestyle plus the planned housing gift is simply too much for the liquid plan, so that case only stays positive after dialing spending back later on (the “safe” line is still around £3,087/month).
Buying requires patience - and comfort with a tight cash buffer for a few years.
In this scenario, the timeline looks like this:
Ages 32–34: save hard while family costs are still comparatively low.
Age 35: commit a six-figure deposit, meaningful buying costs, and some early post-purchase work.
From age 35 onward: ownership costs run moderately above current rent once you include mortgage, council tax, and maintenance.
Mid-life realism: ownership also brings larger repair and upgrade shocks later on.
In practice, that means liquid savings can get uncomfortably low right when childcare starts, unless you explicitly plan a short-term bridge. In these runs, the buy path supports roughly £2,605/month (lower-return) to £3,087/month (base) of safe retirement spending on investable assets alone (the stronger-return buy variant also includes extra late-life family/care spending, so its “safe” number is closer to £3,973/month without tapping home equity).
Because the buy track here assumes family help at the purchase date, the liquid pot stays above zero in the timeline — but it’s still a good idea to keep a separate emergency buffer outside your deposit money.
Both paths assume the full £1,900/month UK State Pension (i.e., two full NI records; Child Benefit can provide NI credits if one parent pauses work). The rent track aims for a somewhat higher retirement lifestyle, while the buy track starts from a slightly leaner investable-asset budget and expects you to plan separately for unlocking home equity if needed.
Remember: all amounts are in today's money. If inflation runs at 2%, the nominal pound amounts you'll actually withdraw later will be higher - but these projections already net that out so you can think in real purchasing power.
Deposits & wrappers: The deposit here comes from general savings. A Lifetime ISA bonus can help only if you meet the conditions (including buying your first home for £450k or less), so for a £600k–£625k purchase you should assume the deposit comes from taxable savings and/or family help. If family help is likely, treat it as separate support rather than part of your emergency cash.
Stamp Duty & price caps: First-time buyer SDLT relief fades above £625K. If your target flat is pricier or this is not your first purchase, raise the buying-cost assumption accordingly.
Childcare support: Tax-Free Childcare adds 20% (up to £2k/year per child) so long as each earner makes at least £8,670/year (and meets the other eligibility rules). Funded hours extend down to nine months old starting September 2025, but most nurseries still charge for meals and extras - leave room.
Child Benefit & NI credits: Claiming can help you build NI credits, but households with one earner above £60k face the High Income Child Benefit Charge. Decide whether to repay the benefit or to claim in the lower earner's name for credits only.
Pensions inside payroll: The take-home pay figures already assume 5% employee contributions with employer match covering the rest of auto-enrolment. If your employer contributes more (10-12%), adjust the take-home assumptions rather than double-counting pension savings.
When you open the scenario, choose the path closest to your situation as the baseline, then change only the assumptions that genuinely differ.
Shift the savings cadence: If cash flow is tighter, test a meaningfully lower saving rate in the mid-30s and a later recovery in your 40s. If earnings rise faster than this baseline, add the extra saving later rather than assuming the childcare squeeze never happens.
Move the purchase window: Bring the home purchase earlier or later to match when you could realistically buy. Refresh the ongoing ownership-cost assumption using current mortgage, service-charge, and maintenance quotes.
Refine childcare and school costs: Swap in your own nursery fees, after-school club charges, or grandparents' help. If funded hours cover more than expected, redirect the difference to emergency savings, mortgage overpayments, or investments.
Stress-test retirement: Try a leaner and a more comfortable retirement budget, then watch how quickly each path loses resilience when you layer on market shocks.
Model home equity exits: Add a downsizing or equity-release step if you expect to tap the property after age 70. Without it, the buy path under-reports your true wealth and may look harsher than reality.
This scenario is an educational planning tool, not personal financial advice. It simplifies UK tax, benefit, housing, and childcare rules so you can stress-test decisions before speaking with a qualified professional.