I go through this as well.
It's not limited to music, yet with music I put more limitations on it than other things I create, for some reason.
For work I do animation, and work in a studio.
We have reviews with everyone, and smaller team reviews.
After you look at something too long, all you see is whats missing or whats not working well, and you can't see a solution because you used everything you got to get it there.
You need fresh eyes on it, not your own fresh eyes, others eyes/ears.
For some reason I think this is harder for people making music than people who make visual art.
Not sure why, but most people I know making music struggle much harder when it comes to outside critique.
Anyways, if you want a solution, set up a critique session with people you trust.
There are people who tell me everything I make is amazing, I dont need them involved in this process.
I need critical, smart people ,who have an eloquent way with words who are capable of discussing solutions.
I need to show them my work, and briefly tell them what I am aiming for, and ask them directly what it needs, then I need to shut up and listen.
I dont need to argue with them, explain why I did certain things, or defend any of my choices.
All I need to do, is shut up, and listen to what they are saying very carefully.
THEN, I can decide what I am going to adjust, change, give up on, pursue, with the next pass on the piece in question.
Whats interesting to me is that if your in a band, or in art studio environment, you get instant feedback at multiple stages.
For example, if you write a guitar riff for your band, you play it and the band is either into it, or not.
I do a first pass on animation (limited poses and frames), then I get feedback from the team.
From there I move forward, getting rid of ideas and injecting things people have mentioned.
This forum can be perfect for that, post your work in progress, get input.
There's something special about raw input like that, where you dont know people and they dont know you, and they give it to you straight.
For whatever it's worth, I've been working on 2 sets of music for over 2 years, and I hardly share it.
I share it when it's time too, then I go re-work stuff.
I think it is though this process that you can truly achieve a feeling of "this is good work," even if you still struggle with the fact that you've heard it thousands of times.
If I look back over the years, there are tracks I have made that I knew at the time were good songs.
Wether thats in a band, or by myself.
I know when I got something special, that reflects who I am, it has my style and it sounds good to me, I would buy it, listen to it over and over if somebody gave it to me.
It's important that I break away from myself and judge it based on "if somebody shared this with me, would I play it again?"
If the answer is YES, then roll with, you're onto something.
Thats as good feeling as your gonna get out of it, and it's important to recognize in this whole process.
I often have this discussion with friends who create stuff.
We all agree on some level who makes great art, but do those people know they are making that, or do they feel just the same in the process?