On the plus side, all the hours of research we tend to put in when a buyer asks a question that you don't already know, expands your own knowledge and makes it easier to answer that question, or related ones, in the future. I've had a lot of questions like that, and now I know enough to whittle it down to a short, simple answer.

I used to provide pretty long, detailed replies to customers who sent through a question, as to me I was just making sure they had as much info as possible to make an informed decision, but a lot of the time I wouldn't even get a reply let alone have it result in a purchase, so now I try to address the question as simply as possible, and just say if they require more info, let me know - this tends to eliminate quite a few tyre kickers and means I'm not investing hours into educating someone else for free. Sometimes it's people who have bought items and they're asking how to use the product in a certain way. I do the same there, offer a few suggestions, and then point them to something like a YouTube video for more detail. Occasionally the questions make me curious, so I've been known to actually spend an hour or so making or testing things, and in that case I just add to my experience / expertise as well as help someone, and usually get a loyal customer out of it (though I guess the return / investment on that would depend a lot on whether you have the kind of items they'd come back to buy on a continual basis, however one thing I do know is that word of mouth recommendations, even for online stores, can be worth a lot).