And the other saying is....
Use it or lose it!
This is so true. I have had motors seize slightly because of non-use, and I have had machines discolor regardless of non-use. Parts will become brittle over time, cloth bags will fray and will dry rot over time even if they were stored near sunlight, and motor oil, and yes I said motor oil, WILL even oxidize over time and will not adequately lubricate motor bearings. So go ahead and use the machines if you want them to remain in operable condition longer.
