Facial oils deteriorate the sealing effect of cushions over time, even with proper hygiene. Don't tighten the headgear when you feel leaks. Over-tightening causes discomfort and pressure points, and can lead to additional leaks.
A mask that doesn’t fit can cause you to readjust your mask continually and/or over-tighten the headgear, which reduces how long it can work effectively. Contact your provider to get re-fitted.
These can be leakage issues, cushions that lose shape, and/or components or cushions that become cracked or torn.