Like the title really how often should a clutch be changed? I have an mbk nitro (same as aerox) It a 50cc on a 52 plate, as far as i know its never been done. Also would a new clutch help at pull off and what sort?
Never had to replace a whole clutch and haven't ever heard of anyone having to ever to be honest. Assuming there is still life in the clutch then a stiffer set of springs would help you benefit from better acceleration.
Ive not heard of people changing them due to old age, check the clutch any damage to it, at most take it off give it a good clean, the clutch bell as well, and as brett said stiffer springs should help you get better accel.