My theory is you should have at least as many guitars as you are years old! How many do I need, well that depends, I currently have 8 basses, all sound different and all play differently. Do I need 8 basses? Yes - if I want the particular sound of a Jazz Bass vs a Thunderbird, then I need the bass to get it. Same with acoustics, I have a Gibson J185, a Martin 000-28, a 1917 Washburn Parlour, an Ovation Matrix, and Ovation 12 String, a Yamaha classical and an Espana twin neck 6 & 12 String. No one can say that any of them sound the same, so again I need all of them. I'm not even going to get into the electrics, but once more they all sound different and do I need a 57, 61 and 63 Strat? Once again they sound different and are totally different to play. At the end of the day that is why I get other guitars (that and also because I like them). So at the moment I have more than I am in age. Just don't ask me about amps - same arguments - they all sound different!