what do you think about redating an ex a few years on do you think like yeh go for it, it could be different, or no theres a reason why they are an ex

the reason why i asked this qusetion is because i was at a house party with an ex who i havnt seen in years and a mutual friend has been trying to set us up, at the party he asked me out but i didnt realy say yes or no just kinda put it off, i used to work with the guy years ago we were good mates and then dated only for a few months before we realised we got on better as just friends but i havnt seen him since he left work few years ago til now.