>>3772950If you have enough memory, use as many layers as you want.
I personally will use a new layer to try something out, if it works I merge down. I try to use as few layers as possible and at some point I always force myself to merge down so that I don't wade in indecision for the entire piece.
Another method is just to duplicate. You work on basically 1 layer, and then duplicate it when you're about to refine. Refine that, and if you mess up you always have the blocking/underwork in the previous layer. If you're happy/satisfied with what you've done, you can delete the first layer and now your new layer that is refined is your 'fall back' layer. Duplicate it and repeat.
Obviously this is a very personal thing. If I'm drawing, its' way simpler.
If doing an underdrawing, that's one layer. Inks are a second layer. It's only when I do painting that I do the other stuff. On extremely rare occassions I will ink something twice.
So one layer is the first inks, second layer is me inking it again to see if I like it better. I think it's super rare for me to like the second ink or any subsequent ink better than the first one.
I very rarely do the above.