Quoth NoACWarrior:

Expel vestige. You have no daily limit on the number of vestiges you can bind per day, just the amount bound at once.
You do, however, have a daily limit on Expel Vestige-- Only once per day. Yeah, it helps, but Buer is still a pretty big chunk of your resources.

To be fair, there are other ways of getting infinite healing from a binder. You could, for instance, bind Tenebrous instead of Buer, and then take Sacred Healing (the one from Complete Divine, not PHB2) as a feat. That lets you turn your 1/5 rounds Turn Undead into healing, while still giving you other useful abilities from Tenebrous. You're still spending resources, though, just a feat and a smaller opportunity cost on the vestige.

And please don't think I'm hating on the Binder. I actually think it's a very well-designed class, and would love to play one if I ever found myself in a game that used Tome of Magic.