Over time, the hard water in our area leaves deposits in the moving parts of the plumbing. When our tub spout diverter clogs, I use WD-40 with its spray nozzle curved up the spout to the diverter ...

Nothing is more annoying than sloshing around in the shower because your tub drains slower than, well, molasses. Why it drains slowly could be from a range of issues–soap scum build-up, hair, a clog ...