It helps me to think of my hobby as a living thing, always growing and maturing. I've taken short cuts on models just to finish them quickly only to go back and "fix" them later. Other models I've done years before, I've updated with new details. A few I've even completely repainted and still others I've totally left alone. I'm currently in the middle of an extensive kit-bash/scratchbuild project that I keep reworking because of new research material that has revealed some detail I didn't previously see. But I know, in the end, I'll be much hapier because I took my sweet time and kept reworking the project, instead of sprinting to finish line.
So to answere your question: yes, you can be finally done with a model, but it might take a while.