How many do I get in a week? At least 100.
How many requests do those queries net a week? Maybe one or two on average (some weeks as many as four(!), but some weeks there are none).
What's my response time? On a one-page query... two-three weeks from receipt (so if you are sending it from somewhere far away and it's snailmail, you need to allow extra time for transit; also, if you are sending it to our old office there probably won't be a reply -- the forwarding order is no longer in effect because it's been a year and a half since we moved to 27th Street).
Here's a pet peeve: Sending me a query letter that's addressed to another agent. (The envelope was obviously addressed to me.) Bad mail-merge technique, I'm guessing. This happens with e-queries too. The devil is in the details, apparently.
Errors in queries: This seems to be a popular scenario... 3 seconds after the query is dropped in the postbox or after the person has hit send, the author realizes they've made an error. Is it a good idea to send a 2nd query with the error fixed asking the agent to disregard the first one? Hmmm, not sure. It might depend on the level of the mistake. I think queries should be carefully proofed (this would also take care of the wrong name problem). Don't forget that they are generally the first introduction the agent will get.
Re-queries (which I understand to mean sending the same query again): I don't think you should send the same one twice unless you've been invited by the agent to do so. I think you could query about a different project perhaps (though I'll admit that when one gets a number of rapid-fire queries from the same person it might eventually start to feel a bit awkward). Of course, I don't want to state any of this as an absolute. The market changes. Something I read 6 months ago and thought I couldn't sell might become more commercial based on shifts in the potential audience. One does try to anticipate, and be somewhat visionary, but still. Plus, I can myself as an agent be in a different place due to various variables. It's an art, not a science.
What am I looking for? Well, it's a lot easier to say what I don't want (like, picture books) than what I do want (after "great stories that I can sell" it gets a bit speculative). Plus there's the problem of discovery. I'm all for trying new things. Once upon a time, for example, I didn't know that I liked sushi either.