IF you paid off a card completely, then closing a card isn't really that bad right? Assuming you keep a low utilization at all times, then the decrease in total credit limit wont really effect you, and if you have 5 accounts that are 10 years old, closing one of them won't do too much hurt, right?
Do companies frown upon seeing a lot of closed cards?
Closing a card with a 0 balance will not hurt you. It will still factor into your AAoA for up to 10 years.
I wouldn't close one unless there was an AF involved.