Beyond someone's personal risk level health conditions, this is also every dependent on the environment you're walking around in.
If you're vaccinated and walking around in an area of low transmission, you're probably back to the "before times" with no care in the world.
If you're vaccinated and walking around in a pool overflowing with uncontrolled high spread, some precautions are still prudent. You're just being exposed to to much virus.
Meaning, lots of this depends on where you're living and hanging out. Either way, you're significantly (orders of magnitude) better off than an unvaccinated person.
If you want to use the CDC levels for what's high or want some other metric where high starts later, that's a different question.