Well, actually, none of them are mine really. I'll just lay claim to this particular arrangement. Credit goes to the forgotten sources that gave us the memes, and life that proved them true.
- Never acquire anything until you really, really, want it -- three separate times.
- The real cost is the lifetime cost, from acquisition to disposal. Or, as per a recent NYT post, think subscription -- not ownership. In the modern world we don't own, we subscribe to something that's neither inert nor living. The purchase price is often the least of things.
- Don't buy on promises or potential. Acquire for real value now. Anything in the future is a plus (or, sometimes, a minus).
- Don't buy more than you can consume now. We all have fixed resources to acquire and adopt new things; acquisitions that sit on the shelf depreciate very quickly.
Rule #3 didn't used to be true of computers. In the days when our computers were open platforms, we could reasonably expect that the market would meet our needs. That's obviously not true for Apple's increasingly closed products; whether it's an Airport Extreme*, Time Capsule*, an iPod, an Air Book or an iPhone. It's also true for Windows however -- there will never be a real alternative to Microsoft Office on Microsoft's platform.
* Alas, how much better these things would be if Firewire had not been eliminated by the far inferior USB 2.0 interface. Another story though.
PS. Ever notice that no-one does a list of "four" things? Three, yes. Ten, yes. Never four. Until now ...