Gain stages on Preamp


What is the purpose of adjusting the gain stage on a Preamp? Does a Solid State amp vs a Tube amp dictate up or down on the gain stage? What are the Pros and Cons of turning it up or down?
Thanks Pete
68pete
05-19-15: Bombaywalla
good answers by Newbee & Viridian. I'll add my 2 cents:
the gain control on a preamp is really an attenuator as already indicated.

Gain control in stages are voltage dividers
same thing (synonym) Czarivey - voltage dividers, attenuators. they reduce/attenuate the voltage coming out of the preamp.
I like using dual volume. In my analogue setup I use Nakamichi RX202 tape deck to provide extra boost to phonostage. That extra boost I can vary from record to record and achieve an ideal volume settings per listening I desire.
yeah, I see what you are saying - the flexibility is good but you have one more distortion-creating device in your signal chain which is not good IMO but if it works for you-great! :-) I feel it's better to have minimum electronics in one's signal path with each device correctly designed for the job. This way one does not need to band-aid.....