Some people have many decks.
While no so common in TCG areas, this does occur quite often, and very often, in OCG dominant areas, due to the cheaper cards(most of the time)
Whilst for many, the spread of cards across these several decks is not a problem, since most will give priority for any cards they need for their main deck to be in their main.
What people do not realize is that they are spreading their focus and development of their playing over several decktypes, meaning the time developing your playstyle for each deck is significantly reduced.
Most good players tend to have very few decks. One or two not so often, but three or four actually quite often.
Therefore, instead of creating many decks(especially decks with themes in common, that draw from similar support cards), if you want to become better and win more often, focus on one or two decks only. Having another deck or two just for fun might not be a bad idea, but try not to deviate from your main deck too often, and have your fun decks bearing similar concepts/themes.
For example, since my main deck is Absolute Zero, my fun deck could reasonably be a Shining based deck, so thus by playing either one, I can develop my playing for a similar deck, and confront certain situations given a similar pool of cards more often.
Asking some of the best players out there, they probally only have around three-four decks, as compared to the upwards fourty most normal players usually have.