It's important to continue asking yourself that question throughout the process. I'm a fan of rough edges so I tend to leave a few in.
A song is never really finished. There are always ways to constantly rework parts, and make changes. As artists, I don't think any of us are 100% happy with what we put out there. But there has to come a point, where you have to walk away from a song, or you will never get any music out there!
For me, there are three states of "done" for a song:
1) By the time I get to lyrics, the instrumental arrangement is already finished, so once I'm happy with the way the two go together, writing is done.
2) Sometimes, I don't care about getting more than a raw recording of the song, to have a document of its existence. For those, the recording is done when the takes and mix are at least good enough to understand how it goes.
3) For songs that I really care about, I'll spend several days listening to various intermediate mixes, identifying mistakes that need fixing (as opposed to those which lend character), levels that need changing, etc., until finally I have a mix that pleases me for several days.
In all of these cases, I guess the short answer is: the song is done when I'm happy enough to move on.
Because I heard it first as a finished product in my head, so I know when it
sounds just right. The song tells me when it is ready to be heard.
A song is finished when the flow is just perfect from the beginning to the end - in my case, a song is done when I listen to it and I feel my heart pounding and I smile.... then I want to listen to the song again. That's the sign for me that says my song is ready.
For musicians, a song never "feels" finished, but there comes a point where you just have to draw the line and move on.
When I can listen to it and go, "There's nothing I need to fix."
i get a lot of feed back from music listeners. and kind of feed off of their energy, because i am making the music for the people. so if it feels good to them, it feels great to me
I don't. I always hear something I could change, or make better somehow. I've never made a song that I'm completely satisfied with. It can be annoying.
different people produce different quality..some take pride in what they do...if im in lead of my tracks...i know when im done after ever word can be understood....and all is blended together...after that,if the mix is proper,then mastering will take its affect.
It's hard to explain and often I don't feel they are done even after they are completed.
You have to have "that ear".You can hear and feel it when it's done.
I just know or I don't. Sometimes it takes me a very long time to finish a song and sometimes it takes me a day. It really just depends on the song.