Female-to-female RJ45 couplers ("join adapters" as described by the article) have been very handy in my experience. They're cheap enough that I don't mind leaving one now and again. It's so handy to be able to unplug something, splice in my laptop / tap / etc, and quickly return things they way I found them without rerouting the original cable. It's also handy when you don't have a long enough patch cable with you but you do have a couple shorter ones.