Addresses are not account numbers. You shouldn't re-use addresses. You should think of an address more like an invoice number. It is a unique identifier that you give to someone so that they can send you a payment. If they will send you a new payment, they should get a new address. You should give a new address for EVERY payment you will receive.
I think this is one of the most difficult concepts to get one's head around. I suspect it's because we "want" to think of them as being analogous to bank accounts, plus of course the shorthand habit of referring to them as "wallets" means one's instinct as to consider them as a place where you put "money" and if you
put it there, then it stands to reason that is where you expect to
take it from.