Nearly one in four first-time buyers say it took them between five and 10 years to build their deposit, research has found.
A survey of people who have taken their first step on the property ladder in the last two years found 23% had been saving for between five and 10 years beforehand.
More than two-thirds (69%) say it took them more than two years to build up a deposit and three in 10 (29%) had support from the "bank of mum and dad", with cash contributions from their parents.
A further 8% were given financial help to buy their home from other family members, the research from Which? Mortgage Advisers found.
Building up a big mortgage deposit can help home buyers to secure access to better mortgage rates from lenders, as they are seen as less "risky".
And taking out a smaller loan as a result of having built up a larger deposit can generally result in cheaper mortgage repayments, as there is less money to pay back. There is also generally less risk of falling into negative equity with a bigger deposit if the value of a property decreases, as the borrower owns a bigger share of their home outright.
But in local areas where house prices are rising strongly, would-be home buyers may also find that certain properties are pushed out of their reach financially while they are saving for a deposit.
Various Government schemes have been introduced in recent years to help first-time buyers get onto the property ladder, including Help to Buy Isas and also Lifetime Isas, which are due to be launched from April.
And the Government recently launched a housing white paper outlining plans to help home buyers and renters.
Which? has launched a free interactive tool at which.co.uk/deposit to help people work out how long it will take to save up enough to buy their dream home.
More than 1,000 first-time buyers took part in the survey.