While I'd hazard that it is far more common, particularly with digital recording, to track each 'voice' to an individual location; as with most things with audio production I doubt that there is any absolute definitive, across the board, 'best' approach. But as it sounds as if you are tracking vocals separately from other instruments you lose a tremendous amount of control and flexibility by not having separate tracks. In struggle to get vocals to have impact you want you typically gain more traction by editing the support instruments
even so it depends on content, performance, genre and goals. I have worked on projects where not only was everything recorded to a single track but done with a single mic. It helps in this case if one is working with top flight musicians, familiar with material and everyone is in agreement on how things are supposed to sound
If room, mic locker, do not sufficiently control bleed then, in terms of time, effort (and hence $) it can be beneficial to mix live to single or pair of tracks. How one approaches tracking a trap set kind of illustrations the options. Do you approach the kit as a single organic 'voice' or put two mics on the kick, top and bottom on the snare, separate mics on each tom and cymbal? In any half way decent room I might derive anywhere from 70-90% of the final trap sound from overheads . . . but even when leaning in the 90% direction I would still prefer to have separate additional tracks for kick, snare, hi-hat, etc. On the other hand if I'm working with a client who honestly (and that's the kicker what clients say and what want are frequently not on speaking terms) wants purely that 'live' sound I might well restrict kit to three mics
there is always a trade off in what ever approach you use . . . in addition to having a preference for slightly less then 13 mics per drum kit I'll frequently use a single mic on elements designed as a single voice even if comprised of multiple instruments: small horn sections, string quartets, back up choral sections, etc. But I'd typically want a client to be clear as to why they wanted multiple voices collapsed, in recording stage, to a single track and appreciate the limitations in adding or modifying anything after that 'print' before I'd pursue a course other then some reasonable count of individual tracks for individual voices. Even so most of the decisions do fall under 'producer' purview with regard to managing personnel and budget and from least experienced to most experienced producers will have individual approaches as well and any that came out of the old A&R mold won't necessarily find any benefit in considering 'talents' opinions.