A word about tweeking older works. As we improve and look back at some of our older paintings we have to make a decision. I do anyway. I don't like to keep bad work. So it has to go to the burn barrel or be tweeked.
The main problem with tweeking older work is the paint thickness. You can't paint over thick paint and do a good job. Besides, it will crack eventually. I'm talking about oils here. That limits the amount of work to be tweeked. Only those paintings done on panels or masonite will survive. Forget those done on canvas. I remove the old paint that is thick or that forms a hard edge with a sander. You lose a lot but you still keep the basic drawing. The panel becomes smooth and ready for painting. Remember, if it was originally painted in oils, you have to tweek it in oils. Acrylics won't stick to oil paint.
I just worked on a half dozen panels and they are ready for re-working. The paintings done on canvas will go to the burn barrel. No hope for them. But before I do this, I shall trace my drawing so I can do the whole thing again on a fresh panel or canvas.