Owning your own home

You can also get offset mortgages that do a similar thing: take the balance of a savings account off the total owed, while leaving it in place, saving you interest payments. But I imagine the account has to be with the lender, possibly a specific product, perhaps not paying much interest... Still.

I've got an offset mortgage and it only works with current / savings accounts with the lender. As an example, if the mortgage outstanding is 100k and you have an average of 10k in the other accounts, interest is only charged on 90k in that year. Meanwhile you would continue to make payments based on the 100k figure so the overpayment would reduce the outstanding balance resulting in paying off the mortgage quicker.

They are certainly worth considering if the initial loan interest rates are sensible.