Physical damage is a judgemental thing, though NEC seems to think anything emerging from the earth outdoors requires at least a jump from sch 40 to sch 80 with no other justification mentioned. I would say maybe 80- 90% of the time that is probably still a good idea though.
Indoors, there is wide variety of what may or may not cause it to be subject to different level of potential damage though.
Inside dwellings particularly the "living spaces" that risk is often pretty low, office spaces and similar often low. retail space - can vary a lot. small store that only has hand trucks and carts to move material around - maybe low risk, if they use powered fork lifts, pallet jacks, etc. the risk goes up. Industrial can have big variety of risk depending on normal use of a particular space as well.