Well where I work its a small family owned buisness but we get alot of traffic in and out. It is alot of contractors and big trucks coming through and they tend to kick up the dust and what not. I park behind the store away from the main parking so I tend to keep it covered as much as possible.
I use to when I parked outside. Just make sure your car is clean before putting the cover on. You may get some scratches if there is dirt/grit on the car and you put the cover on. (some a$$ stole my cover ... cut 2 locks off of it!)
Very good points. The other downside is that the cover will eventually get nasty on the outside and then you have to clean it. Might not be the easiest task you'll want to do. I was never a big fan of covering cars outside when parked. But if you're in an area where bird droppings are a constant issue, a cover will help preserve the paint. But....the downside again is having the cover get nasty and you either have to clean it, or store that nasty cover in your trunk. Just something to think about.