I probably don't change my needle as often as I should, but do try to change it with the beginning of each new quilt or the equivalent, i.e. about 15 blocks. I use Schmetz needles that I almost always buy when JoAnnes has its Notions Wall at 60% off. Mostly I use topstitching needles size 80 as they have a nice BIG eye that I can see to thread!!! LOL