IME, use of compression totally depends on the style of music, density of the arrangement, where you want the vocal to sit psychoacoustically in the mix, and the consistency of the vocalist/musician.
I use compressors (and sometimes limiters) for several things:
1) To make the volume level more consistent between soft and loud passages
2) To make the place where the vocal sits in the mix more consistent at different playback levels (limiters especially useful for this)
3) To emphasize the proximity effect and/or feeling of intimacy on a vocal and make something seem closer in the mix
4) As an effect to alter the tone of a track, pump it a little, or affect the attack/decay envelope to bring out certain features of the sound (though I generally do this more with guitars, bass, and drums than vocals).
5) Compensate for bad mic technique of a vocalist or wildly dynamic bassist or guitarist in getting consistent levels to tape.
So of these considerations, only #5 depends on the talent, but yeah, it does play a role.
I generally do not find compressors useful as a tool to keep a vocalist from getting too loud or overloading the signal chain. For that I use a pad switch, gain knob, etc. If they consistently go from too quiet to too loud in the same take, I either split the track up into sections or try to find a mic/mic position that evens out the dynamics.