Trading and investment platform Interactive Investor surveyed 10,000 Brits approaching or in retirement and found only 25% admitted to having written a Will.
Shockingly, 70% of retired respondents have no lasting Power of Attorney.
However, leaving an inheritance is a top priority for 35% of respondents.
Only 19% of non-retirees opted to hire a financial adviser for retirement guidance, with most favouring a DIY approach.
This included online research (42%), reading the financial press (28%) and using a government-sponsored guidance service such as Pension Wise (23%).
Retirees, meanwhile, tend to prefer professional finance advice, with 29% paying a financial adviser on an ongoing basis.
But this still ranks behind DIY online research (44%) and the financial press (34%), with only 11% looking to family and friends.
The survey also found more than a third of women (34%) describe money management as a chore compared to 15% of men, although 21% of women said it gives them a sense of satisfaction – half the number of men (40%).
Fitting money management into their schedule seems to be more of an issue for women than men.
Overall, most people think they have time to adequately take care of their own finances (87%), but 19% of women (19%) said they do not, compared with 9% of men.
Retirement makes a big difference – 97% of retirees said they have enough time for money management compared with 75% of non-retired.
Men are more confident that they are sufficiently well-versed to manage their finances than women (79% versus 56%) and tend to spend more time on it.
Women (30%) are twice as likely than men (14%) to spend less than an hour a month managing their finances.
In contrast, 29% of men said they dedicate up to six hours a month to managing their finances, compared with 12% of women.
On average, one to two hours a month was the most common length of time people spend managing their finances (30%).
This does not bode well for the income potential of women at retirement.
Research found that almost half (48%) of non-retired men already do, or plan to, derive some of their retirement income from stocks and shares ISAs, compared with just 18% of women.
Some 36% of non-retired women regret not saving enough, while 33% have no idea what their income will be in retirement.
As for men, 28% of the non-retired regret not putting enough money away, with 19% unsure of what their income will be in retirement.
In addition, 32% of women believe the overriding meaning of retirement is uncertainty around their levels of wealth compared to 17% of men.
Overall, not starting a pension sooner is the biggest financial regret among 17% of respondents.
Around a third (32%) of non-retirees rue not saving enough more generally and 12% regret sitting on too much cash and not being invested in the stock market.
Poor investment decisions is also a top financial regret among respondents (17%).
Moira O’Neill, head of personal finance at Interactive Investor, said: “This survey presents a more nuanced picture of what retirement (and the run up to it), looks like in Britain.
“Many of our retirement priorities take significant planning and, overwhelmingly, this research finds that peace of mind, not running out of money, and having enough money to leave behind to children are all top objectives. In other words, many want to have their cake and eat it – but it is women in particular who are more likely to be left with just the crumbs.
“Overwhelmingly, this research puts real flesh on the bones of the gender pension gap, and it is concerning.
“The inescapable truth is that many women are facing a retirement of financial hardship which is having a real and lasting impact on their quality of life.”