Back to the origional topic (heaven forbid)
I will "master" everything I do unless the band want to send it to a mastering house. Which in the case of indie bands in my area is not very often.
However I have some basic guidlines.
1. - a reference CD that they sort of want it to sound like. So I can match tone (in mix) and loudness. My stuff won't be nearly "as good" but it's nowhere near as expensive and most bands will realize the tradeoff (while I work to minimize it)
2. a few days off from the music - the longer the better. So I come back with a fresh mind.
3. The client must realize that the production is "low budget" ...however I get most of my clients because I'm better than the local studios ...or at least more fun to work with

I mean studios in my area pull crap like recycle (heavily used) tape and I had one client who was referd to a studio by a weathy friend...the studio took control of the project and obliterated it... went from good Christian Folk to really bad CCM...when the friend heard the CD he refunded the $3000 (one week) to her himself.
heh...infact I went digital when I started because every local band that was recorded on tape had crappy production quality.
In my old band our fans actually liked the production of our very first demo (vegas audio and SM57's into a 8 track mixer into a soundblaster card) in a noisey basement than at Rome Recording in Columbus, OH (second demo)
You just have to know what you want and be careful and patient.