I want to make sure I learn all the Thu'um, and in order to do that, I need to acquire quite a few dragon souls. Should I put off the main quest as I slay dragons and find hidden draconic words, or is this a non-issue?
Clarification: I know the dragons begin spawning after a set point in the main quest. The main crux of my question is whether they stop spawning after another (later) set point in the main quest. There are infinite dragons during the main quest, but do they stick around forever?