Annuities are a vital part of the pension system for millions of people, but their sale has been described as "disorderly" by the City watchdog.
Not everyone needs to buy an annuity, but retirees who do only have one shot - as they are buying a retirement income for the rest of their lives.
So, what are annuities and how do they work?
What is an annuity?
Individuals save into a pension during their working life and so build up a pension pot.
At some point during the first years of retirement, they will usually use this lump sum to buy an annuity from an insurance company.
This is a transaction that occurs once, and only once.
An annuity is an annual retirement income that is paid to them for the rest of their life.
Does everyone need to buy one?
No. Those with final-salary pensions will be awarded a pension pot linked to their salary when they finish work, so will not need an annuity.
The state pension is also unconnected to annuities.
There are also options for people, primarily those with a very small or very large pension pot, to draw money from the pension pot in another way.
The latest estimate is that 420,000 annuities are sold every year. As more and more people are enrolled automatically into a workplace pension, these annuities will become even more common.
Does everyone get the same deal?
First, there are standard annuities - available to all. Then there are enhanced annuities that can be bought by people with a lower life expectancy, generally smokers or those with a medical condition.
The latter are more generous because the insurance company is betting that they will not have to make the annual payment for very long.
When it comes to buying an annuity, retirees need to look at the rates on offer.
A bit like finding a good savings rate?
Yes, a little like that.
Just like savings, the financial crisis has had a big effect on the rates on offer. For many years rates were falling, but they did start to recover last year.
Ultimately, retirees need to shop around for a good rate, and often take a guess on the best timing. If they think the annuity rate might rise, then they might delay buying an annuity.
Do I need to buy the annuity from the same company I saved with?
No. You have the right to shop around.
A review by the Financial Conduct Authority found that six out of 10 people stick with their original pension provider.
Some 80% of those could have had a better deal if they had got their annuity from a different provider.
Where can I go for help?
This is a big financial decision and one you only make once, so it is well worthwhile doing your homework.