It seems fewer and fewer manufacturers are offering re-webbing services. As Calkins states it is usually nearly as inexpensive to just buy a new set and sell the old stuff on the internet to somebody who doesn't care about dates (mud / rock crawlers, sports car racers, vintage racers, etc.). Some manufacturers will discount a new set if you send back your old stuff.
I always wondered why belts had such a short life. Yeah, I get it that some owners let them drag on the ground up the return road, get sun faded from UV, soaked in trans fluid, etc., but most of the sets I've replaced look like new when removed. It would seem to me that replacement could be a judgement-call-attached-to a-sunset clause, i.e. if your belts look OK at the discretion of the tech guy you can continue to use them up to an extended cut-off date. The rule seems to be aimed at an exceptionally few bad occurrences. How many of us replace the belts in our daily drivers every two years?