There's always the sorta new scam..sending people bills for magazines they get, and a lot of folks will simply send a check to whatever address is on the bill. Most of us, me included, never remember what address goes to what, especially since companies change owners now and then.
You should keep a running file of what you've paid for what, and how long it is for and when it will expire. Might surprise you to find yourself being billed for a magazine you've paid a year for only 2 or 3 months before!!