Six Pension Mistakes to Avoid That Could Cost You £10,000s

The pension mistakes to avoid are not arcane technicalities: they are straightforward errors, repeated across millions of savers, that quietly drain retirement pots by tens of thousands of pounds. With the UK government’s Pensions Commission warning that around 15 million people are on course to fall short of their target retirement income, and 45% of working-age adults saving nothing at all, the stakes are not abstract.

The pressure is sharpened by a rental market that is closing off one of retirement’s traditional safety valves. Standard Life’s August 2026 analysis projects that rents could rise from £1,160 a month today to around £2,350 by 2046, based on a 3.8% annual increase using Office for National Statistics private rental data. Over a 20-year retirement, that accumulates to a total rental cost of £419,000 nationally — rising to £859,000 in London and remaining highest in the South East at £531,000. Research from the ABI, cited in the same Standard Life release, found that one in three pensioner households could be renting by 2044. Currently, 82% of retirees own their home outright, a cushion future generations cannot assume.

The income implications are direct. Pensions UK Retirement Living Standards set the minimum single-person retirement income at £13,900 a year, assuming housing costs are covered. For a retiree renting, an additional £13,910 in annual housing costs pushes that minimum threshold to £27,810 — almost doubling the baseline requirement.

The Six Pension Mistakes to Avoid

Steve Webb, partner at pension consultants LCP, Helen Morrissey, head of retirement analysis at Hargreaves Lansdown, and Daniela Silcock, director of Daniela Silcock Pensions Research, identified the six errors most likely to leave savers short.

1. Losing pension paperwork. The Pensions Policy Institute’s 2024 Lost Pensions Survey puts the value of lost pension pots at £31.1 billion across 3.3 million separate pots, with an average pot size of £9,470. Webb noted he has ‘lost count of the number of people who have contacted me asking for help tracking down a lost pension from a previous job,’ adding that ‘those who have kept paperwork have a far better chance of success.’ Old workplace pensions can be traced through a previous employer via Companies House, or through the free Pension Tracing Service.

2. Ignoring employer matching. Under auto-enrolment, workers earning more than £10,000 a year contribute a minimum of 5% of salary and receive at least 3% from their employer. Many employers will match higher contributions. According to Standard Life’s research, someone starting work at 22 on a £25,000 salary who raises their monthly contribution by just 1% could add £26,000 to their final pot. Webb described the matching arrangement as ‘an incredibly efficient way of rapidly building up a pension pot, as every extra contribution is effectively doubled overnight.’

3. Not claiming higher-rate tax relief. Around 800,000 people failed to claim higher-rate pension tax relief worth over £1 billion in 2023/24, according to a Freedom of Information request by Webb. Basic-rate taxpayers receive relief automatically, but higher and additional-rate taxpayers in ‘relief at source’ schemes must claim the balance themselves. Webb’s explanation of the arithmetic is precise: ‘If you pay £80 into a pension you get £20 basic rate relief making a gross contribution of £100 into your pension. But having made a gross contribution of £100 you are entitled to £40 relief if you are a higher rate taxpayer, not £20, and £45 if you are an additional rate taxpayer. You only get this if you claim it. The missing amount is £20 per £80 that you have paid in, which could amount to thousands of pounds for some people.’ Claims can be made via a self-assessment return or through gov.uk.

4. Transferring a defined benefit pension unnecessarily. A defined benefit (DB) scheme provides an income for life, typically inflation-linked, and may continue paying to a surviving partner. Silcock warned that once transferred to a defined contribution (DC) arrangement, ‘poor returns or high withdrawals could mean that the money runs out.’ Transfer can make sense in specific circumstances — terminal illness, or wanting to pass funds to a wider group of beneficiaries — but the default should be caution.

5. Starting too late and contributing too little. Silcock illustrated the cost of delay with a straightforward example: £1,000 invested at age 20 at 5% annual growth reaches £7,040 by age 60. The same £1,000 contributed at age 50 grows to just £1,630, a difference of £5,410 on a single contribution. The compounding effect makes early years disproportionately valuable. For those who cannot currently afford to contribute, Silcock suggested exploring whether a partner can make contributions on their behalf.

6. Assuming a full state pension. The full new state pension pays £241.30 a week, but receiving it requires 35 qualifying years of National Insurance contributions. Career gaps for caring responsibilities are common, particularly among women. Morrissey was direct: ‘Don’t assume that you will receive a full state pension. If you’ve spent any time out of the workforce, you could have gaps in your National Insurance record that mean you get less.’ Voluntary NI contributions can fill gaps, though whether that is cost-effective depends on remaining working years and individual circumstances.

A Renting Future Changes the Maths

The regional disparity in projected rental costs underscores how unevenly the burden will fall.

Source: Standard Life, August 2026. Based on 3.8% projected annual rent increase using ONS monthly private rental data.

For Londoners facing a potential £859,000 outlay in retirement rents alone, the six pension mistakes to avoid become rather less academic. The Pensions Commission’s interim report, published in May 2026, will not finalise its recommendations until Spring 2027. Until then, the levers that individuals can pull — employer matching, tax relief claims, early contributions — remain the most direct response to a savings shortfall the state is still working out how to address.