“A répetition of this kind was considered to be an original and autonomous work. A repetition on a smaller scale than the first work was referred to as a réduction.
“…Van Gogh set out in works like [his sunflower paintings] to improve a favourite subject .”
— Marije Vellekoop in Van Gogh at Work, page 191
When you’ve finished a painting, take all the “what if I” and “maybe I should” thoughts and apply them to a new canvas. Do another version of the painting, aiming not for an identical twin but a sibling, similar but not exact. It helps you develop ideas further, see what results if you do try something you didn’t before for whatever reason, gets things out of your system for better or worse.