Gonna depend how you use it. Spray washing vs trying to achieve agitation by reversing direction intermittently.
I don’t actually have data because I was ONLY using a ring of felt, and vacuuming the spent biomass out (and hence the felt) every time. I was also loading directly into a spinning rotor, and was definitely missing often enough that I really do mean that should up above.
The way to tell your bags/liner need cleaned is to track the weight of your biomass. Set a cut off for how much solvent you loose, and call that your service time.
You should probably visit It washes the cannabis and then it washes the cannabis some more