Age is no problem - he'll be 31 in April ffs. He's got at least 2 years left in him if not more.
As for fitness, well, we get him as fit as we can but it's never really stopped him doing damage in the past.
Agreed. Hibs signed Franck Sauzee (of French international and Marseille fame) at age 34 and he stayed for over 2 years and still is the best player I've probably ever watched in the flesh, certainly when it was on a weekly basis. 31 is not that old, and I say that as a 31 year old!!