Right on, prevention is way better than the cure! Wish I had taken the same step. The gnats ended up spreading a mysterious fungus to the roots that killed one of my clones from the inside out... had to kill 3 additional clones to stop the spread. Now I know why they are call fungus gnats. I am using mosquito dunks (same bacteria)to keep them at bay along with neem drenches.
The real bad bugs are spider mites and root aphids (very tough to eradicate). I have spotted about a dozen root aphids recently but haven't seen any mites for about a month.
Investing in some neem for preventative soil drenches and some azamax ($25 for 4oz) for mite and other bug control might be a good idea. If you see a mite treat it like an act of thermo-nuclear warfare! I grow in a garage and have a cat so that contributed to my problem I think. Definitely dont go directly into your grow area if you have been outside in grass or on a hike etc.