Threebly

Any excuse to post this baby otter and I'll take it.

With an acoustic drum kit, one generally wants to record some elements to separate tracks in order to not have the sound bleeding from various close microphones when they're otherwise not doing anything.
For instance, on tom drum tracks (back in the olden days of analog tape) one would actually listen through a whole song and erase all of the sound on those tracks between drum fills. The result was to help reduce the squonky squishy sound the mics at the toms would add to (say) cymbal tracks.
I think that with entirely sampled drums I nominally need to only work with six tracks.

1. Kick
2. Snare
3. Toms L
4. Toms R
5. Cymbals L
6. Cymbals R

Now note that the "cymbals" are not "overheads" as they would be in a normal recording of acoustic drums. They're actually separate of, and divorced from, the toms. But let's back up a moment.
The kick and the snare are almost always given their own tracks for a couple reasons. One is that the sound of each of those drums is typically extremely important to the overall sound of the drums and of the piece of music being performed (in our case, rock music).
But the other thing is that they can do a marvelous job colliding with other instruments. The kick absolutely needs to work with the bass (guitar or keyboards) in order to complement rather than compete with the low end.
The snare drum is typically in a fight with the singer although in almost all the music I've done lately we've been instrumental so the snare is just arguing with guitars. This argument is easier to calm down if you can equalize and compress the snare separately from the rest of the drum kit (especially the kick drum).
So -- why split up the toms from the cymbals? Well, it's mostly because the toms will likely get more compression and more reverb than the cymbals. They'll certainly get different compression from one another. Could we put toms and cymbals on the same track? Well, yeah. In fact there (used to be a) school of thought where you'd put cymbals and maybe hihat on the kick track because you wouldn't have to worry as much about them interfering with one another. But that's only when you were on an analog machine and desperate for tracks. Those days are long gone.
This is just some rehearsing betwixt Lily, Greg, and me. Lily is on drums. Sometimes I'm on bass, other times on guitar. I'll let you guess which is which.