In the case of fixed-rate mortgages, you can only remortgage when the agreed term comes to an end. If you leave a mortgage early, you will have to pay an early repayment charge. However, you can already start preparing to remortgage two years before the term expires. In the case of SARON mortgages, there are contracts with minimum terms that must be complied with. You have to bear in mind that many mortgage lenders position their borrowers within a staggered system of terms of different lengths – e.g. five-year or eight-year fixed-rate mortgages. This makes it far more difficult to remortgage because the possibility of placing an individual tranche with another lender is so slim. If the different tranches do not expire within two years, it is practically impossible to switch lender without paying a penalty. In this case, you remain locked in to the same lender for a very long time and, when one tranche expires, you are likely to be in a poor negotiating position. Accordingly, there are few cases where staggering the tranches of a fixed-rate mortgage makes sense. An exception would be if you wanted to pay off one tranche in full after its term expires while proceeding with the second tranche.