Why the consternation? This is smart. ...and good for your corals and fish. I will always buy extras and more of the things that are core to my personal method. Real live rock from tear downs, tunze pumps, askoll block pumps, good halide stuff, reactor media, bags of good sand (found some southdown lately), life reef skimmers, calcium reactors. At ten cents on the dollar and not much room to store, it is good to have backups on hand. I try and avoid buying anything techy since five new versions could be out before I get around to using them. I have a drawer of fittings and stuff too.
I do not have much junk anymore which was hard at first and then I felt so much better when I got rid of it all. I got rid of all of my empty tanks too.
Decided that if you have an extra LifeReef skimmer, then that is ok. However, if you have an extra SeaClone skimmer, then you might have a problem.