I know just what you mean, I have at least 3 rifle projects that have been worked on and off for the past 2 years. My problem is I keep buying more guns when I find something unique or at a price that is so good I cant pass it up. Then the ideas for modifying them starts and I get started on another gun, the projects that I can complete within a week I can get done start to finish.
A couple of the projects that have been sitting require , rebarreling, making a new extractor/ ejector, bushing the firing pin hole thru the breechface, and complete stock refinish so I have to be ready mentally before getting back at it.
Being retired you would think there would be plenty of time for good stuff like building and shooting guns but its not so.
jedman