If you have a default on your credit file then it will remain there for 5 years. This is if it has been paid. If it has not been paid then it will remain on your credit file. How lenders treat defaults depends on the severity of the default(s). Quite often though you will have to go with a non-conforming lender and effectively bide your time until you credit file has improved.

Here are some examples or how lenders treat different credit issues:

Defaults < $500

Many borrowers have Telcos defaults. Most lenders will ignore these or most defaults under $500 if you have a reasonable explanation

Paid Defaults > 2 years

Some lenders will treat defaults that have been paid out more than 2 years ago as if they have never happened.

Strong Financials

Some lenders are willing to consider overlooking blemishes on your credit record if you income is particularly strong and you have a good reason.

Bankrupts

Bankrupts need to have been discharged. Even then the options are limited.