i switch between that stuff and the kiwi brand spray. whatever is on sale at the time. they work about equal from my experience. i pick up 3 cans a few weeks before my trip when i pull everything out and check it over. the tent rainfly gets a full can, the tent bathtub gets a can (heavy on the corners/seams) and then another can goes on my pack/pants/shirt/shoes/anything i have laying around.

gotta let that stuff air out for a bit(after its completely dry) before you pack it away, i usually leave my stuff on a clothes line or in the garage for 3-4 days. then pack up the tent with a few dryer sheets so its smells fresh!