I don't think I expressed myself very well above, but feel like trying again.
My problem is with the term cycle.
Suppose a person starts a "cycle" of discs by beginning with one driver such as a Destroyer. He throws just that one disc for a while, and know that it serves the purpose for certain throws, but is just too overstable for many situations. So, he gets another Destroyer that turns out to be a bit less stable. With these two discs he now is able to cover more types of shots, and is happy with the results. But, over time, the less stable Destroyer becomes even more understable until he notices a gap between his Destroyers. For some reason, the more stable Destroyer is holding its stability, and is still quite overstable. So, he looks for another Destroyer to fill in the hole between these two discs. With some trial and error, he comes up with the new third Destroyer that perfectly fills the gap. Now, with three Destroyers to his arsenal, he feels very well served with what he has got.
Unfortunately, the most understable one is lost to an errant throw. He is now back to two Destroyers, and wants another to fill the place of the one that was lost. So, he once again searches, and over time acquires another Destroyer, perhaps a used one, that can approximate the flight of the one he lost. He uses these three Destroyers for a time, but eventually decides that the newest disc is in fact not quite a good replacement for the lost disc. So, he searches again, acquiring several candidates for the understable Destroyer spot, finally getting one that will serve.
Unfortunately again, he loses another Destroyer, the middle stability one. Since the most overstable disc still cannot replace it, he tests his growing pile of backup Destroyers for a candidate and replaces the missing middle stability disc.
Over time, the above scenario could be repeated multiple times. When a disc is lost, or its flight changes, it could be that none of the other molds currently bagged can truly replace it, so a replacement is sought out.
Has this person cycled Destroyers during this time? I would maintain that he has not. To me, a cycle requires that each disc is handed down to a less stable position in order. If the order is broken, then I do not like the term cycle for it.
In my hypothetical scenario, the only definite cycle is that the person looks outside for replacements. With this practice, a person could theoretically replace a disc with any other mold also. It need not be another Destroyer.
Just because a person has several of one type of mold in their bag does not necessarily mean that they are cycling that mold. So, when a person here states that they bag several of one mold, and are cycling, response is, "But are you? I have no way of really knowing." In fact, I think it would be a little too perfect in the real world if a person's cycle were in fact working out. Disc golf is just a little too messy to believe it.