I start new projects faster than I finish old ones

I had the same pattern for a long time. What helped me was a hard cap: no new project until the current one is either finished or formally abandoned. Writing down 'abandoned' felt weird at first, but it stopped the pile from growing.

Three half-done projects is not that many, honestly. How long have they been sitting?

Not every project needs to be finished. Some are just there to teach you something or keep your hands busy for a while. I used to beat myself up over abandoned things until I realized the value was in the doing, not the finishing.

What actually worked for me was reducing the number of projects I allow myself to have open at once. I picked two. If I want to swtart a third, I have to close one first. It is annoying for the first month but it forces a decision instead of letting things drift.

copperkite_88 has a point, but I think there is a difference between a project that taught you something and one you keep telling yourself you will finish someday. The second kind just sits in your head taking up space. I started putting a deadline on things I actually want to finish and letting the rest go on purpose.

A year is a long long time. Maybe the real question is whether you still want the result, or you just feel bad about the sunk time.

I don't think there is a single fix. Some people do well with hard limits, some need external deadlines. For me it was having someone else waiting on the thing, even a friend who just asks about it once a week. The accountability did more than any system I tried.

One other thing that helped me was keeping a list of every project and marking honestly which ones I would start again today if I had the time. Most of them I would not. That made it easire to let go of the rest.