If the cartridge wears out, your shower valve won't function properly. (Indicated by leaking or seeping water.) The rubber rings and parts around the shower valve may need to be replaced, as these shower components are susceptible to breaking, corrosion, or dry-rot.

Do I need to replace shower cartridge?

Difficulty regulating temperature or water flow is an indication that you need a new cartridge, but it could also mean the old cartridge is simply blocked by mineral deposits. If it's the latter, you should be able to see the deposits. Soaking the old cartridge in vinegar will probably dissolve them.

How often should you change your shower cartridge?

Because many types of bacteria thrive in moist areas like your shower, it is recommended that you replace your shower head every 6 to 8 months. Keeping your shower head clean, especially if you have hard water, can be very difficult to manage.