The thermostat on a tumble dryer controls the extent to which the air is heated, thus ensuring it's at the optimal temperature for drying your clothes.
The thermostat can end up getting damaged or becoming faulty with regular use. You'll be able to see if the drum in your appliance is no longer turning as it should, and whether your clothes are staying damp and no longer drying.
Your tumble dryer may also start overheating, or to do the opposite and no longer heat up at all.
Find and order the right thermostat to fit your tumble dryer right here. Large number of models available!