Most importantly, check the cost of servicing, if service kits is readily available and where to find trustworthy technicians. Many shops claim to be able to service your regulator but they lack the proper tools to do the job, so its up to you to trust their words.
As long as there are no visible cracks or dents, the regulator should be good as it is build to last. Many people had regs that lasted 10+ years. Also check the hoses as well for visible cracks. if you are not sure, send it to a servicing shop for checks.