Call me crazy, but I have been known to lug a pair of bolt-cutters and several quick-links up routes to perform required maintenance. No need to close the route/pull the chains down, since it's maintained in situ. Simply cut the worn links, install the new quick-links, bring up the second, and move on to the next station. The QLs are replaceable by anyone with a wrench as they become worn in later years, so shortening of the chains is not an issue.
My problem has been to convince someone to belay me on these ventures, as they are somewhat time-consuming (especially the multi-pitch routes) and are not most climbers' first choice of use of time while at the crag.