Old showerhead always came out with little pressure and unevenly. Cleaning didn't help much so I looked for a new one. I found a seller that manufactured locally and specialized in showerheads. Much better than the attractive plastic junk from the box stores.
It was an easy change and it makes a big difference.
Many shower heads come with a setting that cuts the flow of water.
For the most part, it works ok but if the water flow is too low, the water sets in the pipe long enough to lose a lot of heat into the pipe and throws off your water temperature anyway. Also, most of the designs aren't really designed for you to manipulate them with soapy hands, which would be exactly the reason you turned off the water.
So, unless I am somewhere with expensive water or have a reason to take an extra long time standing around being soapy, then I rarely bother.