I do usually save between battles in WRPGs, and if a fight goes especailly horrible, due to some really stupid choices on my part, or I'm just not happy with how it turned out and felt I could do better, I will reload and redo it.
During the roleplaying sequences, I generally don't save scum on my first play through, unless it's a Bioware RPG, and the dialogue choice didn't reflect at all what I expected my character to say, at which point yeah, I'll reload.
Each person might see a rose with a different shade of red, but the fact that we can all agree on is beauty -- that is a miracle. -Michea, FFXI
A lot, especially right now in KOTOR 2. I know I did this a lot in XCOM and Valkyria Chronicles. Behind her Blue Flames DLC for VC takes RNG waaaaay too far. I had an enemy dodge Selvaria's attacks 4 times in a row. Seriously, if it wasn't for her, there's no way in hell the Imperial's would be able to conquer part of Gallia.
I did that to for a bit in Fire Emblem: Awakening on Hard-Casual, but half way through Chapter 18, I just couldn't be bothered. If a unit went down, they're sitting it out until the next skirmish.
It's funny how No Guard and the absence of it can turn the wimpiest of men into fighting machines and gods of war and destruction into pathetic, big, wimps.