This is one of those rather obvious questions, but is one that bears remembering even by yours truly. The clear fact is that any eq adjustment must only be based on how it relates to the big picture of the mix. It’s tempting to solo whenever you get deep into working on a particular sound, and there’s nothing really wrong with that when you need to get after a particular bit of a track. However I recommend to do it only when you can’t quite hear what it is that’s going on. Sometimes there’s a particular resonance that’s bugging you and if you can’t hear it, then sure...go ahead and solo it.
Here's a great tip in such cases; Select a narrow Q and turn up the gain and sweep the frequencies to find the resonance that’s not working. Once you find it, then duck at that frequency, experimenting with the Q to see how wide it needs to be. That’s useful especially for snare drums which have a tone which isn’t helpful. Sometimes a note in the drum is great, but sometimes it can be in the wrong key for the song, so then you really need to duck it.
So try to resist the urge to solo right off the bat. Work at it for a while while in the track, then solo if you must. Just make sure you don’t get in the bad habit of soloing every track when you need to eq.