Depends on the band's budget, ability and ambitions. Most of the time if it's feasible to quad track, I'll talk the band into doing it. As well as giving a denser sound, it also gives you an opportunity to work with blending unique guitar tones, rather than sticking to one amp. I know you can signal split to multiple amps and cabs, but that approach has too many inherent phase coherency issues that I'd rather not deal with if it can be avoided. Anyhow, at the very least I will try to coax quad-tracked choruses out of an artist, particularly if it's a commercial rock outfit. It's worth noting that having a mix varying in density is arguably even more important these days than dynamic variance since most mixes will get brickwalled to the shithouse. Splitting your song structures up so that you've got the cliche sparse verse (all room verb, 2 guitars, lower gain, back off drum compression) dense chorus (kick in the lexicon, 4 to 8 guitars, start redlining the 1176) can help, and doing more than 2 rhythm guitar takes can certainly help with varying density. That's just my take on it.
