Star,
I like the way u think! Bravo.  I get bored by my old images.  Even if I'm not very pleased with them, I add new ones every few days... just to shake things up, if only for myself. 
Sometimes I'll have an image up for a day or so, then take it down... just for variety. 
Nice thread.  Interesting to read!

Every shooter needs a model or two that they can "play" with, their muse as it were.

As well, most of the models that I know have their "favorite" shooters that THEY feel most comfortable with trying new ideas and approaches.  Models can have muses, too.

I think that it depends on what you are trying to do with your photography. If you are in the world of fashion photography, a lot of different looks in your work will show experience and versatility.
I have no training in photography, and I am looking at things from a background in art, but I know that Andrew Wyeth, a very respected, famous artist, did 240+ drawings/paintings of a friend of his named "Helga" over a 15 year period. He did other well-known works, but he is probably most famous for the "Helga" collection. 

I don't shoot for profit.  This is my hobby, so I may have a different perspective.  I like to shoot with the same model for as long as she can stand me.  I have a friend whom I've been photographing for the last twenty years.  We've made thousands of images together.  One of the women on my MM page has been sitting for me for ten years.  I enjoy these long working relationships the most. 

I admire how many different looks Petter Hegre has gotten from his wife, Luba, and still keeps it fresh.