With all of the idiots on CL, I wait at least 24 hours before I respond to any emails. And, I go through them and respond to the ones that are intelligent enough. If it seems like a high maintenance buyer asking stupid questions that are clearly answered in the ad, they don't get a response. Consistently bad grammar and misspellings? No reply. Ect, ect...

Is it being a prick? Maybe. But, I'm not going to chase anyone down for money or have my chain jerked around. My time is valuable to me. Worse case scenario is I have an extra bike kicking around, which is far from a worse case scenario. They always find a home, eventually