Well I didn't count my addresses on exchange sites because I don't consider them part of my wallet.
I suppose that's true since the address might be yours, but the wallet still belongs to the exchange. I would still technically consider them as my BTC addresses. Without them I would say I used roughly 100+ addresses.
You've got that right. It could be considered your address in exchange's wallet.
No matter how much security an exchange offers, it always makes me uneasy keeping my coins there for an extended period of time. Nothing beats having your own wallet.
Well I don't keep anything on my address on exchange site. I find it unreliable to hold any amount of money for a long period of time.