Updating Older Armies... Or Not?

I guess we all face this problem, sooner or later in our hobby.  For some of us, we've faced this several times.

What I mean is this: what happens when your painting skills outstrip your finished armies?  Do you repaint it or leave it alone?

Here's an example of what I'm talking about, my Homage Space Marines.  I'll probably do a full army feature at some point, just to hit the nostalgia button for some of you long-time gamers.  Fact is, I love the RTB1's and all the old, first edition Space Marine.  Hell, I love all the old models - there's something there that appeals to me.  I remember how excited I was when I first got involved in the hobby, and this old range brings that back every time I use them.

Anyway, I grabbed the first layer from their box and set them up for these pics.  Basically, should I bother updating the paint job?  I can strip 'em and repaint them fairly quickly, or perhaps touch up each model, defining the highlights and inking the green areas... but is it worth it?  They're done, after all.

So my question is, how many of you have gone through the same thing?  Do you have the constant urge to update or repaint all your old models?