Sorry if I wasn't clear, but baked AO required the scene to be static, however the lighting environment can vary. Meaning you can blow out lightbulbs, bring a torch, move the sun, etc, but you cannot change the scene itself. Objects that can move will need to be excluded from the baked AO. Generally I think having AO on the non-destructable parts of the scene, like floor, walls, ceiling, etc is enough.
Of course there's always the option of using SSAO instead but in my opinion it looks bad and requires a lot of GPU power to compute. I think using baked AO on the static parts of the scene is a good tradeoff as opposed to not using any AO at all.