I wear my contacts pretty much all the time, especially when I'm doing an athletic activity. The only problem I've had with drying out is when I have them in too long, but that usually means 24hrs+ (basically, what you're not supposed to do). You can feel it when they get dry, which is easily remedied with wetting drops.

My problem is that my eyes water a lot if I go fast enough, for which I wore wraparound sunglasses this summer. But now that it's fall in New England(where temperatures dip to what you'd be riding in), and cold air is hitting my eyes, I feel like I need to get goggles (especially for riding at night/ in the dark), but I can't find a decent pair.

I'm nearsighted, I dont' know if things would be different for someone with astigmatism.