Back in the day when reciprocal linking was useful, some webmasters were trigger happy and aimed to link to everything that would link back, even if there was no relevancy from site to site. Over the past few years, many of those reciprocal links were not as reciprocal as they used to be, as other webmasters became savvier and realized there was likely no value in these links.
With this being the case, a webmaster has looked into his links and noted that it's probably about time that he should revamp his "directory" of links. Should he dump everyone (especially the irrelevant links) or just a few select individuals who aren't linking back and aren't relevant either?
Forum members at WebmasterWorld suggest to keep only the relevant links (and pages that actually exist) and inform all webmasters that these links are to be dropped. Additionally, you don't need to necessarily aim for a 100% reciprocal link ratio. Instead, it should be "somewhere between 30-80% [reciprocal link ratio] which shows the search engines you are linking for your end user and not necessarily for reciprocation."
Forum discussion continues at WebmasterWorld.