I try to have a general idea of what sounds I want in advance. With the thousands of sounds available, you risk never getting to the end of a project (given too many choices, no choice can be made).
As an example, I may have a recording in mind that will require bass, drums, accoustic guitar, electric crunch guitar, a lead guitar solo, a "Rhodes piano" and a synth pad. I would normally have an idea on which bass sound and which snare sound, a guitar sounds, etc. etc. so I dial those up.
Now maybe after I record the crunch guitar, I may decide the piano needs a brighter attack, or the synth needs to cut through more, etc. If possible I'll simply dial up another piano or synth sound, or possibly just try to EQ the sound I already have.
When I first started to work with synths (many years ago) I spent way too much time trying to find "just the right sound". Looking back, I could have recorded 3 more songs in the time I spent trying to dial up the right "synth sound"
If the song is good, the sounds are simply frosting, thus not worth a significant amount of effort.
MIDI is great because it allows so many sound choice options (you can delay committing to a final sound until the mixdown )- however, it can also cripple you from making a final decision and simply living with it.