If your shower power just ain't what it used to be, the showerhead could be clogged with mineral deposits. No need to replace it, though. Gently unscrew it from the pipe and soak it overnight in vinegar. (If you don't have that much time, a 50-50 mixture of hot water and CLR,
a powerful calcium dissolver, will do the job in a few minutes.) Then wrap new Teflon tape clockwise around the pipe threads and turn the head back into place.