I've only been diagnosed 3 years now, but it has affected me and I think that because I didn't get it as a youngster.
I evaluate everything now, so plan ahead, where I'm going to be at what time and for how long, what food am I going to eat etc. I also get into an odd state now when I meet new people as I worry about having a hypo in front of them, so for instance on Tues I had work men coming round and as I had to explain a lot of information and there were 2 of them I got a bit paranoid that I was going to have a hypo and possibly embarrass myself in front of them, I worry about hypo-ing a lot too. Also a friend recently suggested about doing a trip to the Amazon and my immediate thought was I cant go cause I've got this, I still don't feel I could go even with some after thought. The only positive is that I do more for others now as I don't accept things at face value.
Ok I eat better food now too and look after myself more but it has definitely changed my outlook.