A smart way to protect your wellbeing is to bring a few masks on you. You will determine when it will be easiest and safer to dispose of the recycled mask and put on a new one with the following indicators:
Whether you have to have to touch and readjust your mask in order to properly shield your mask and nose. A snugly fitting mask should leave no holes or need a little change.
Test the ties on your mask and the elastic loops. If the band constantly loosens or slips off, it may be yet another indication that the mask no longer suits you well. It may also be an indication that it has begun to weaken the cloth.
If after frequent washings, the cloth becomes porous, or light and thin.
If you observe holes or rips on your mask of some sort. This is one of the most troubling failures that could be harmful to you. Swap the mask out quickly, no matter how small or deep the opening is.
Best of all, swap it out for a new one if you want to be healthy and wonder whether the mask makes you feel insecure in any way.