I have never seen filters in the laundromat dryers.I’m with your daughter, always after the load is done. Because that is when it collects .
When you go to a laundry mat you would clean it when your done even though you have to check to see if someone didn’t clean it when you start because people don’t clean it.
I clean mine right after I empty the dryer, which is usually right before I pull the just washed cloths from the washer to put in the dryer
