Somewhere there is a definition for the word "boat" that is "always something more to do." Back when I lived ashore, I had a similar list for the house. Most of those projects were somehow easier and faster.
I set some ground-rules about projects for myself:
1. Make sure I have a complete plan;
2. Make sure I have all the parts I need;
3. Make sure I will leave the boat in a sailable condition;
4. Only add projects that will make the boat easier to sail, more comfortable, or safer; and