If your shower runs at mains pressure or close to it, it's quite possible that you can reduce its pressure without detriment to its cleaning potential and how it feels. Indeed, if your shower is like mine, it might actually be painful to stand under at high pressure. It seems that most modern houses comes with thermal store hot water systems which allow hot water to be delivered to the house at mains pressure, without little regard to what is actually comfortable or what is economic and eco-friendly.
Since I have the luxury of two showers I have installed two different devices, one in each as follows:
Eaga Shower Smart (get one free)
A small pressure-reducing insert that goes inline with the shower hose.
The Eaga shower smart prevents the unnecessary waste of water without loss of comfort. It creates a constant flow of 7.7 litres per minute, giving a full even jet with less fluctuation in water flow. Water temperature can be more constant - because sudden changes in pressure have a much smaller influence on the temperature.
For a 2 person household, the Eaga ShowerSmart could save more than 12000 litres of water per year, as well as all the associated energy costs that go with heating it.
At the time of writing Eaga are running a promotion for a free showersmart.
Oxygenics BodySpa shower head
If you want the dual benefits of economy AND a spa-like experience when you shower, then try the Oygenics BodySpa shower head. The entire oxygenics range not only reduces pressure and flow but at the same time sucks in oxygen and mixes is the with the water, giving an incredible refreshing shower sensation without any feeling of loss of pressure.
I have one fitted in my main shower and have tested that it does indeed reduce the flow (easily done by filling a bag with a line marked for 5 seconds or so) yet it feels wonderful to shower under. And it looks great too. The single orifice design of Oxygenics® showerheads coupled with internal components made of non-stick Delrin® are no match against common "shower cloggers." There isn't a calcium deposit or sediment that will stand in the way.