Had ours for 5 years with no trouble. We have never heard of any yearly service required, unless it is some kind of cleaning service, etc. Wipe it down every time you use it. The prices have dropped the last 2 years or so, i would not get an extended warranty. The only exception would be if it is an odd size or has an unusual cut out (drop in) that in case it did die, you would probably not have to get new a counter top too.
Smooth tops can get very hot and will warp thin bottom pans/pots, especially the aluminum ones. Once the pans start to get concave or convexed bottoms, they don