I think Qantas FF do a better job than most in informing all their members that points expire after 18 months of inactivity. It's not hidden anywhere.
I can sign into my Qantas account, and I have to work out when the points expire. I can't really find it anywhere (maybe it's there, but not so easy to find). I sign into my AA or UA accounts, and right beneath or beside the points balance is the expiry date.