I think that a DJ will never learn the benefits of having a good speaker and monitoring system until they actually get the chance to use one.  The most Spartan bedroom DJ out there makes use of only a few tools to mix their music.  They need a computer (which we can consider to be mid range in performance), they need a pair of headphones (these can be cheap), and they need a controller (which can be cheap as well).  Together, they need little else to mix their music.  However, the minute they begin using proper sounding speakers and headphones, they realize just how many more errors are revealed in their work. The idea here is that better sound quality and sound clarity allows you to think deeper into how you mix.  You might be off at every single down beat of a newly mixed song but not realize it on a crappy pair of speakers.  Those muddled up sounds actually help you hide your transitional errors within a song.  A new way of approaching this situation is to add audio clarity using an audio interface.  This ensures that your speakers are getting the signal they deserve midway through the chain.  http://www.synthtopia.com/content/2013/07/10/2013-summer-namm-antelope-audio-showcases-orion32-interface/