In my current state of technology addiction I am more discriminating, and I am much less likely to make a gadget purchase if it isn't something I'm sure I'll use at least once per week. This is a much more sensible (and economical) approach. However, this line of thinking has me wondering what exactly constitutes a gadget, so I'm going to take a stab at defining the properties and qualities of a gadget:
1) A gadget usually requires electricity. (Some very cool gadgets also make use of magnets, which probably involve electrical activity at some nano level by a solid-state physicist's definition).
2) A good gadget never costs less than $5 and often costs 1-2 orders of magnitude more.
3) A gadget is always portable and can be carried in a pocket or backpack. A helicopter, for example, cannot be a gadget, even though it uses electricity, costs more than $5, and is portable from a certain perspective.
4) A gadget is self-contained (i.e., it doesn't necessarily depend on another gadget to function).
5) A gadget can operate from battery power. This doesn't mean that all gadgets use DC power, but all true gadgets can.
6) Gadgets require input, usually from a human. This can be kinetic, sound pressure-based, or photo-based.
7) Gadgets always include some form of metal.
8) Gadgets have a focused purpose, or are good at doing only a few things at most.
I'm sure I'll think of more rules of gadgets later, but this is a fair start.