What you are doing is worth doing
Climbers call them pitches — a shorter segment of a climb during which it is impractical to rest or stop or look back.
In between pitches there is a rest stop — a ledge or even a toehold where evaluation and planning can take place and safeties can be set up for the next pitch.
Climbing the pitch and resting at the stop are split up because there is no room for doubt midway up a pitch, where stopping takes as much energy as moving ahead.
OK, so that’s the analogy, what’s to take from it?
Let’s look at your next pitch: the one you are in the middle of, or are planning to climb:
Small side project? Microscopic part of something big? You’re maybe not as good as the Best? Not pro-grade? Probably won’t come out like you want? Iteration 1 of N?
This doesn’t affect that it is Worth Doing.
If you’ve considered it, then dismissed it because of its minimal impact or shaky quality, don’t. That is like the climber who is questioning why they are climbing midway through a pitch. Instead know that it is Worth Doing, and that throwing yourself behind the task and pushing ahead takes no more energy than stopping and questioning.
You either invest each moment in doubt or outcomes.
If you continuously evaluate if what you are doing is Worth Doing, while you are doing it, you are doing an expensive real-time opportunity cost calculation — it is a constant and continuous energy draining audit of outcomes before having them available to audit. Save this evaluation and retrospection — it is meant for specific milestones in a project (the rest stops). In other words, if you aren’t fully behind what you decided to do, you are looking over your own shoulder the whole time, questioning instead of doing.
How would it feel if someone else were doing that to you? Yeah, so don’t do it. Cheer yourself on like a good climbing partner, and have your own back.