Do professors tailor recommendations to universities? Preferably from a professor's candid viewpoint. When writing graduate recommendations for an undergraduate, do professors write general recommendations describing why #insert name# is a great fit for graduate school or do they tailor each letter to the school. I know this can vary from professor to professor, but what is a common practice. 

I ask because I will be applying to graduate schools (quite a few of them on my list currently) and just wondering how much extra work each school is for my professors.
Professors often write just a single general letter about the student and send that everwhere.

Advantage: don't feel shy about applying as many places as you want.