A record number of people are now part of a credit union, with membership hitting 2,020,470 in 2018, according to the latest Bank of England data.
This is part of a growing trend, with the member numbers up 2.6% from 2017, and a 15% increase from five years ago.
Despite this, credit unions often fly under the radar. So, can these groups offer competitive savings and loans, and are you even eligible to join one?
Which? explains everything you need to know about credit unions, whether you should join, and how they could benefit your finances.
Credit unions don't have corporate shareholders taking a cut of the profits, leading many to believe members can earn far more than 'normal' savings accounts.
Rather than earning interest, you'll usually be paid out of the credit union's dividends.
While this can be more lucrative - Find Your Credit Union says you could earn up to 3% - it's not guaranteed that you'll receive anything at all.
Despite the increase in membership, the dividend payments for all credit unions across the UK have been in decline since 2014, with only a very slight increase in 2018.
The graph below shows the overall dividends paid by credit unions across the UK, with data sourced from the Bank of England.
If your dividend is shrinking, your savings risk losing value in real terms.
If you don't, it means the cost of goods and services will be increasing faster than your money, diminishing your spending power.
Of course overall figures tell you little about the performance of any specific credit union. You should always check your chosen institution's recent dividend payment record before deciding to deposit your savings.
Just like 'normal' savings accounts, some credit unions will specify an AER interest rate on their savings accounts.
My Community Bank is one such example. It has several fixed-rate accounts, lasting for one year, 18 months, two years and three years. At 2.35% AER, the two-year account offers the second-highest rate on the market for this term.
This is beneficial to those who want to know precisely how much their savings will grow by.
Credit union loans are often cheaper than other providers, especially for amounts up to £3,000, because there are usually no set-up fees, admin costs or early redemption fees.
Interest rates also tend to be low. By law, the amount of interest charged by a credit union can be no more than 3% a month on the reducing balance of a loan (an APR of 42.6%), but some credit unions offer interest at just 1% a month (12.7% APR).
The BBC reported earlier this year that nine credit unions went bust in 2018 - the highest number since 2010, when 10 defaulted.
Indeed, in the past 10 years, 73 credit unions have gone bust, and 400 have wound down their books and closed since 2000.
But the wider problem is troubling. The increased up-take suggests credit unions are offering services people want, but more members aren't necessarily a guarantee of healthy finances.
Credit unions have been around in Britain since 1964.
These non-profit financial organisations were traditionally set up and run by members that shared a 'community in common' - such as their profession or where they lived.
For some, this is part of their appeal. With no corporate profits to earn, the money goes back to the members who borrowed from and invested in the organisation.
And as of 2012, credit unions can allow multiple groups of people to join. Whereas membership could once only be based on location or profession, now membership could involve individuals who fall under both groups, or other common bonds.
That said, some credit unions voluntarily keep only one type of common bond in place, so you'll need to check if you're eligible before you apply.
Credit unions usually offer savings and loan services for their members, but some have also branched out into mortgages, current accounts and prepaid cards.
Editor's note: This article was amended on 8 August to reflect that credit union memberships still require some kind of common bond to be fulfilled to be eligible.