I found that with the approach I use, a half hour is simply too short, so I only do 1 hour sessions. It's fifty dollars, and most of the folks I work with are already experienced or professional. Generally, with beginners, I reccommend they learn the basic chord forms (with a few suggestions on alternative fingerings) and one solid right hand approach (either strumming or fingerpicking). That's the time consuming stuff, and I just don't think they need to come week after week to learn that....gets too expensive. Once they've shown some commitment, we can work on the tips and tricks.

Cheers

Rick