I listen to my iTunes music library almost constantly when I’m working. I currently have 3476 songs in iTunes which works out at around 12.4 days worth of music. This may seem a lot, but considering how much time I spend on the computer, I burn through tracks with surprising ease.
One of the problems with this is keeping your music collection interesting. You’ll want to hear newer songs more often than older ones, yet at the same time you’ll want to make sure that the old music doesn’t get lost. You want to hear your favourite songs slightly more often than everything else, but you don’t want to keep listening to the same old tracks over and over again. As such you need to make sure your playlists have a good degree of variety as well as and a high churn rate.
I have around 5000 songs on my iPod now. And following his sipmle suggestions, it did boost up my listening experience. I don't get to hear the same song more than once a week...