Our shower head used to get blocked all the time. I had to unblock it twice a week, and ended up soaking it in a sink full of vinegar every couple of weeks to unblock the nozzles.
Eventually we ordered a new one, but meanwhile I found a simple solution to stop the shower head clogging up: tilt it at an angle.
Now when a shower is finished the water drains off properly and it now only ever clogs very slightly at the front nozzles.
This sort of angle seems to work well.
