Synthetic oil......really?

[Intercooled]

I just got my oil changed in my work truck. They suggested a synthetic because my milleage is getting up there (106K). I said "sure" and went with a Durablend by Valvoline. I'm big on maintenance and keeping things is great running order. I have always put regular oil in my H2. I'm starting to think about a blend or full synthetic.I know have 29k on it. I was brought up with the theory that if you changed your oil every 3k miles religiously that youd be fine and your engine will run for a good long time. I always change the oil every 3k in my vehicles. I do use Mobil1 in my Grand National because that was what it came with from the factory and the turbo. So....dealing with the H2, I want to keep this truck for a good long time. Is synthetic necassary? will it help prolong the life of the motor? Any issues changeing over to a synthetic? If you use synthetic do you go longer between changes?
Thanks for your help.