Originally Posted by
biertje
Can you still redeem from a flight 2.5 years ago?
Different programs will allow for different past flights, but I've never seen anyone credit beyond one year, and typically much less.
Originally Posted by
biertje
So do I just sign up to Star Alliance or do I go with a specific airline?
You have to pick an airline program and sign up with it. The sticky at the top of the forum should help you decide.