Rock climbing cams often have integrated slings. Like all webbing, these slings can be degraded by UV and wear out much sooner than the cam themselves. There are numerous companies that will "professionally" resling cams.
One of the advantages of reslinging a cam professionally is the loop of the sling will closed with a bartack (as opposed to knotted). While sewing machines capable of bartacking are not cheap, anyone can buy one. Is there some sort of accreditation that one should look for in a cam reslinger?