Hi Ken, usually you'll find it's guitarists who mic up their amps, as they like the sound that comes out of their speakers to be fed into the PA. Typically this applies to a lead player, so the soundknob, sorry, soundman can balance the volume when said guitarist is soloing.
I have found in the past that, imho, far too much is fed through the PA - in a smaller venue you can often get away with nothing being mic'ed except vocals (and hirns if you have 'em); mics on drums, guitars and DI on bass are used too often as far as I can see, which can make for a lousy onstage sound. If less is mic'ed up, you probably won't want such a sophisticated
foldback system, as the clarity onstage will be improved, maybe just wedges for vocals. Also, I have found that with nowt but vocals through the PA, once the balance is set the out-front sound has much-improved clarity too. All too oftenwith everything going through the PA it[s the vocals that get lost.
A medium-sized club I play at fairly regularly has wedges, side-fills and a big ol' speaker on a table at the back for the drummer (separate mixes available all from the one desk), all of which works fine onstage, if a little muddy, but out-front, with everything running through the PA it can get quite horrific if the guitars and drums are very loud, which they usually are.
In jazz clubs, it's quite different - usually only a small PA for the horn(s) and vocals, very often only one or two mics, plus sometimes the piano is DI'ed, also very often the speakers are placed at the back of the playing area so they function as combined out-front PA and monitors, or there is one wedge monitor in front of the horn/vocal mic.
What kind of band are you involved in, Ken? How many members, etc? Do you get to do much blowing yourself?
Cheers, Bob