How often do you take the sideplate off your revolvers, for cleaning, and what do you do?
It need not be removed at all. I clean according to the instruction sheet or manual.
Solvent on brush, a few passes through the barrel and each charge hole; while the solvent "works" in the barrel and charge holes, I use solvent on toothbrush (not the one I use on my teeth), brush top strap, frame window, bolster face, cylinder face and the ejector and ratchets and under the ejector, end of barrel and anywhere else that has powder fouling.
I use a dry shop rag or old t-shirt to dry off the exterior surfaces. I then use a clean patch to dry out the barrel and charge holes. A little oil on patch or mop is then used to put a light coat of oil in the barrel and each charge hole. A drop or two on the finger tip is used to apply to the exterior surface of the revolver. A final wipe down with that shop rag or old t-shirt makes it ready to go.
Unless dropped in water or a mud hole, or unless exposed to constant blowing dust or fine sand, such as in a desert environment, there is simply no need (at least during the first 50 or so years of its life) to remove the side plate. I can speak to the 50 year figure from personal experience, although I have friends who say that 60 or more is the right amount.
Perhaps once every few years, it might not hurt to apply a single drop of oil to the inside of the action through the opening created when the revolver is cocked or that little space behind the trigger, after which you work the action a few times to spread it around. Too much oil will just attract gunk over time.