Shower drain clogs yearly after clearing - call plumber or DIY?
in homes with lots of women, or men with long hair, this is a constant battle.  the only way to prevent this is to put a hair catcher over your drain, but these are a nusiance.  primarily the problem comes from hairs getting stuck at some bend or sticky area in a pipe, and this acts as a scaffold for more hairs to accrete and so on and so on.  if you regularly pour a bottle of some sort of sodium hydroxide based drain cleaner down the shower drain (say once every week), it will be the best you can do to prevent it, as it will regularly be cleaning the pipe and attacking any hair that has accreted in the previous week.

the only permanent solution is to convert the drain pipes to a larger size and a smoother finish (eg. remove old 1.25 inch copper and replace with 2 inch abs) all the way from the drain to the main stack.