Just to let you all know if you have credits left and won't be using them for a while, you lose them, even if they show up that you have them left. I topped mine up in September and when I went back at Christmas they didn't carry over.
I used to have a Nokia 3310 and that worked fine over in Calis with a Turkish SIM, they don't need to be triband as long as the phone is dualband, so I am told.
Farmer, I'm sure if you phones are only 5 years old they should be alright they're not that old, check with your service provider or where you bought it from as they should know. Those people from the shop might only want you to buy a new snazzy phone from them!!!