Can you paint on canvases over and over?

yes..paint KILZ on first

Crackle paint has also been called popcorn paint, and although once very popular, has reduced in popularity over the years. Painting over it can be somewhat difficult, but here is a link that...

if you try to paint over already chiping paint it will peel right off after it drys just scrap as much of the paint off as you can, when you scrap make sure you go in every direction

If you are painting over a semi gloss paint you wand to use trisodium phosphate or TSP on the wall before you start painting. This is a deglosser that will allow whatever paint you are using to...

Yes usually it depends on the paint. If it is a lighter color than you usually can. But you want to wait until the first paint dries.