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.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.
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.