I ride every day but I don't DEPEND on it. I have a car and drive it if I need to, like when picking up large/heavy stuff, etc.

I used to ride regardless, but I've changed a bit and now won't ride if there is more than about 2 or 3 inches of unplowed snow on the ground.
Tired: If I'm tired the best thing I can do is to ride. If I drive in I'm pretty much useless all day. Cycling wakes me up.
Sick: I'm much healthier and take less sick time when I'm riding daily. I've never used up all my sick time since I started cycling, but I do have the option of working from home.
Overslept: I don't really have a work schedule, my boss just wants my work to get done.

EDIT: I have no idea why my posts are suddenly all bold. I'm not doing it, promise. It's just happening.