How much quantizing do you do?

I’ve always gone by sound and feel with my recordings, other than to edit some midi drums and keyboards to build a fill or correct flubs on a keyboard part, or add extra notes after the fact that I couldn’t properly play.
I listened to a few Reaper tutorials today, and found some methods that make getting everything to fit the grid a lot easier than the slice and slide procedure that I’ve used in the past. I got a little overzealous trying to match up a syncopated and doubled guitar part today, but I should be able to fix it when my blood pressure comes back down.
What I’m wondering is how many people on here go through their tracks completely and quantize everything in a project, and what method do they use, or how much leeway do you give yourself?