I got a 50% off deal on a 3-month subscription to Playstation Plus the other day. There was one or two freebies that I was interested in (Quantum Conundrum!). I discovered that I again have access to games I downloaded when I had a free trial a year ago or so. That tells me if I let a subscription lapse and pick it up again, I get my freebies back! Very nice.
It was hard to find this information out, now I know first-hand.