Hi AH ...
As allthumbs mentioned, I'm more of a 'follow the chords' kind of player, that is, using the notes of each chord as it comes and goes as the main notes for any solos. Chords, to my mind, give you a much quicker and more concise access to the 'good' notes and that's because the chords themselves have already selected from the mother scale those good notes. That takes a different mind set that thinking scales. You take the piece of music one chord a time rather than seeing it as under the influence of one scale.
The key of the piece is the main dictator of scales, though, if you'd rather think along those lines, which is what most players do, it seems. So if the tune is in the key of C, simply look to the C major scale as being the batch of eligible notes; if it's C minor, look to the C minor scale. Pentatonic scales, being 5 note scales instead of 7, have sifted a couple of notes out, making it a bit easier to zero in on those strong notes, but the danger with them is that you get locked into muscle memory runs that cease to be real solos and just become scales ... at least that what happened to me when I tried them out years ago. Melody was always my goal when soloing, and I find melody in the chords.
The key, which dictates the scale, also dictates the chords which are built on the scale, so either way you arrive back at the same batch of notes ... it's just that following the chords is more direct, and also automatically takes care of any 'outside of the key' chords that may be included in the composition ... and that's more often than not.
So, bottom line, determine the key the piece is in and look to the scale associated with that key. Modes come into it too, but I won't even broach that subject here, except to say that if you're following the chords, you never need to think about modes ... with just a little bit of knowledge about the chord functions within the key, they're taken care of.
That's my take on it anyway, after 46 years of poking around fretboards.
The topic of following chords is the subject of my book
PlaneTalk, by the way.