I didn't see anything about not using it for 3 months. I have used mine since the very first day I got my car. My only problem was it was tough to put it on by myself but with some suggestions from the forum I am able to get it on much easier.
I don't think the cover is cheap looking at all and it would have to fit tight if you keep your car outside or the wind would pull it off.
I use mine all the time and I would be curious of someone can confirm the 3 month thing because I haven't seen that any where.