When does the painting end?

     I don't consider myself to be a "good" painter.  My miniatures come out looking alright, and I'm not embarrassed to put them on the table, but I tend to think of them as "OK".  I like to think though that my skills have improved incrementally over that past 35 years or so that I've been painting, and I like to think that they continue to improve.  All of this leads me to my habit of retouching and adjusting my miniatures over time.  I find that as I learn a new technique, or get better at an old one that I tend to go back to miniatures that I'm fond of and try to improve them.  Eyes are something that have always vexed me, so generally I would avoid them, which goes against the whole "faces and bases" mantra of what makes a good miniature.  I've been practicing on eyes though and just updated the barbarian in the center and the dwarf to the right with new sets of peepers.  The dwarf was finished years ago, and the barbarian much more recently, yet both found themselves in the improvement line.  I had used the Doomreaver to the left in an Iron Kingdoms game for quite some time but was never quite happy with his Fellblade, so I repainted that last week as well.  The improvements have been incremental, but I find myself now much happier with each of these.
     So, do most people find that they adopt a "done is done" attitude toward their miniatures, or do you find yourselves going back for regular touch-ups on your minis to make incremental improvements?