Yeah it wont be as bad to apply it outdoors, things can return to equilibrium, biology and nutrients can creep in again and cycle more easily. I don't even care about fungus gnats outside things eat them or the wind messes up their ability to fly and reproduce but indoors they can be a pain.

Amazed you have had bug free all this time. Perhaps it's because some of the plants in the house I don't initially grow could be part of the issue too. If the plant is healthy enough it should naturally shun the pests, but some pests are still harder to shun that others!