db wrote on Dec 3^rd, 2010 at 7:21am:

I have stopped bothering with a second pr of pants in summer. Cold weather I'd consider it but rain pants and long-johns work too.

I don't take a second pair of pants either. Running tights are even better than longjohns: Besides being warm, they weigh nothing, take up no space, and dry very quickly. Cheapest place I've found is web-order from Holabird (Baltimore area). If you can find your size on sale, the price is quite reasonable too.