When you have a leaking or problematic shower valve your first thought may be to replace it and be done with it. While it is true that in some cases you just have to bite the bullet and replace the entire shower valve it isn't always the case.
Many times you can fix a shower valve by replacing the cartridge. A new shower valve cartridge can save you the time and money needed to change out the complete shower valve.
Take a look at how easy it is to replace a Mixet shower cartridge, a very common shower valve, and avoid changing the entire valve.