Ask HN: Maximum length of time to respond to an email?

I struggle with this kind of stuff too, I'll have drafts sitting around forever while I ruminate on my writing. Asynchronous communication provides the opportunity for perfectionism, and I have trouble resisting the urge to over-edit.

The best trick is to parlay it into another medium, or at least send a brief acknowledgement of receipt. Taking a complimentary tack works well: "Your question was so insightful I will have trouble conveying a satisfactory answer unless we chat"

Don't make them wait. If you want to answer the question but need time to make sure the answer is the correct one, I'd send them an email that basically says "I want to give you the best answer I can to your inquiry, but it's going to take me a little time to answer adequately. I'm working on it now, and I should have it over to you by XXX"

Of course, you want to make sure you give them a realistic timeframe and make sure you commit to it.

Blasdel's tip about parlaying it to another medium is pretty good as well.