I use the 99.9% stuff just to mow my lawn!

In cities, don't bother with the head nets. You probably won't even need repellent in the urban areas themselves (downtown Anchorage, central Fairbanks, walking from your car in the parking lot to the Alaska Native Heritage Center, etc.). Wherever there's vegetation, though--from Earthquake Park in Anchorage to the campground just east of Tok--you'll need the strong repellent. And in the extreme backwoods, the headnets might come in handy.

I only use repellent when mowing my lawn (especially in the early evening--people here mow lawns at 8-9pm!) or when out hiking. For every other day of the year (working at my office, shopping, whatever), I never even notice the mosquitoes. I did, however, when working nights on the Alaska Railroad in the Fairbanks rail yard!