If you plan to never fly anywhere but SLC you're fine. I'm sure you get winds over 20mph a few times each year. If you want to fly then without wrecking your equipment you'll want to have a full vent in your bag. Granted, it will stay in your bag most of the time, but when you need it and don't have it . . . .
I have 14 Rev kites and several home-made quads, not to mention dual and single line kites. Most of them don't see the light of day as often as they should, but when the occasion presents itself, or I'm just in the mood, I have what suits the situation.