The reason most libraries get out of control is people don't tag the music. This is what I do when i download tracks i'm going to DJ with (im buying mixed in key + platinum notes tonight, so i dont do those steps currently, however I will be). -Download track -Run through platinum notes (correct volume etc.) -Run through mixed in key (detect BPM + Key) -Add to iTunes -Convert ID3 tags to 2.3 -add the year and genre -I also add "Title - Artist" to the album section. This makes it easy on the CDJs to browse the album section, as you only see the name of each track once, then when you click on the album all the remixes of that track are in the one spot. Is quicker to browse through then the tracks section. -I also move the featuring artists from the artist section into the title. I think its more habit than useful, but it helps keep the artists part of iTunes cleaner. Then i go and add to recordbox for it to analyse and transfer onto usbs. Tagging everything like this makes it very easy to then find the music you want quickly in iTunes, either using the search, or can also use the column browser, by genre, artist and album. As far as playlists are concerned, i usually just make them for a specific night/set i'm doing. If i'm going to do a gig, i might make a couple of playlists (e.g. warm up tracks and peak tracks playlists) for that party, making a mini pool of tracks to draw from for the night. I will choose current tracks that i think people will be into that night, plus any requests i know they will want. I may not stick to it, but if i can't think of what to play, ill just reference that playlist. I will admit it is time consuming, but if you spend the time tagging songs properly, you can have quite a large library and still have the ability to find everything quickly. PS, this is just my system, other people may hate it, but find what works for you