In addition to the other reasons given: Sometimes it also makes sense if your income is lumpy and you e.g. expect to have years where your income will fall into

In addition to the other reasons given: Sometimes it also makes sense if your income is lumpy and you e.g. expect to have years where your income will fall into a lower tax band. It then can pay to suddenly recognise more income to take out as much as you can within the lower band.