Good tip. I've heard that one before but I forgot about it. I replaced our showerhead a while back because our utility was giving away low-flow showerheads, but it's definitely been more than 6 months.

Cannot remove the shower head? Then take your solution and put it in a one gallon freezer bag and using a twist tie place the bag up around the shower head and hold it into place using the twist tie. After a few hours continue with the project. Works like a charm!

How often is this needed if you have soft water? More or less often?

Soft water really does not cause water hardness issues with shower heads. Most folks do this when the little openings on the shower head begin to clog up and not spray properly. So if this is occurring on your shower head, then its time. There is no real timing to doing this, just when it needs to be done. However if you find this happens a lot, more frequent cleanings should be considered as doing it more often will shorten the time it takes to get the job done.

Well duh on my part! Thank you Woodbridge. I'll just tell myself it was very late and I was tired when I asked that question. We've never had any build up in the eight and a half years we've been here. We built it.