The goal you keep changing may be serving the wish to begin more than the wish to finish.

Starting carries a pleasure that finishing does not. A fresh plan is clean, full of promise, and free of the dull middle where nothing feels impressive. So when a target keeps shifting, the shift is often protecting that opening feeling rather than answering a real change in circumstance. Each revision buys another beginning and postpones the part where you find out how it went.

Look at whatever you have redefined more than twice and leave the definition alone for a week. Work on the version you already have, including the unglamorous middle of it. Finishing once teaches more than three good starts.