Instrumentalists bring instrument, internal pickup, lead to own amp, spare, amp, mains lead and spare and mains splitter. And mains extension lead. And tuner. And music stand if required. And a light on it if required.   Please. If the man with the PA doesn't give them an instrument mic from their own amp, XLR, DI box etc, they usually just turn their own amps up to 11 so for fox sake sort it.

The pointy head who likes amps brings the rig. He may or may not be part of the band but believe it or not he makes more difference to the sound of the band than almost anything else. If there is no pointy head, the singer brings mic (at least equal to the power of all the other amps put together plus 400 watts if there is a full kit drummer NOT using the PA rig), lead, amp, 2 speakers and speaker poles approproate spares and no-one else gets to use it. If more than one singist, they need to sleep with each other or otherwise reach acommodation.

Electric bass players need to be told VERY FIRMLY they will not be mic'd but DI'd.

People with particular foldback requirements should bring own foldback speaker and power amp (and mains lead and spare and mains extension).

If bass and kit drummer want to be in the PA and loud, they should share the cost of subs, rentalised if need be.

Anyone with wireless stuff should be told to take it home unless it cost over £1,000.

Singers who want Shures (although there are far better vocal mics) should bring them. Singers who want Behringers should be shot. As should anyone who wants Bose anything (except power amps).

Full kit drummers (if they want mic'ing) should bring own kick mic, 3 tom mics, one snare mic, all mic stands, mic cannon-cannon leads, and if they want condenser overheads, mic channels with phantom or a phantom supply.   

Anyone who wants more reverb on the timbali in their foldback should join a different band. Now.