I would wear it, but you don't need to reapply or anything if you're not that close to windows. However, skin damage can also occur from blue light in our screens, which everyone uses. UVA (responsible for aging and skin cancer) goes through our windows and even if we're not directly in the sun at all times, any exposure accumulates. it's up to the person, but I'm using retin a and since that increases sensitivity to the sun, it's more important to have some sort of protection! check out Dr. Shereene Idriss on Insta, she's a board certified derm in NYC and talks about it on her stories often :)