I was struck this morning by how things have drastically changed over the years in the publishing world. This aspect is for the better.
I sent a proposal for my Louie-the-dog thriller to an editor at a major New York publisher. It was an email describing the project. I do a slew of these weekly, concerning various manuscripts. Within eleven minutes the editor responded and asked to see the complete manuscript as an attachment. Within the half hour I had complied. I don't know how quickly I might get a reaction (I have waited more than five months after this point before). My appreciation is for this initial quick turn around (for which I thanked the editor).
I come from a time when, the initial query from the author (me) plus three sample chapters, was mailed via snail mail to an editor. Then, one expected (yes, expected and accepted) a three month wait before there would be any reply at all. If there was a positive reply, then one sent, via snail mail, a hard copy of the manuscript (sometimes two). Then one could expect (and accept) a three month to half a year wait for some kind of decision. Phone calls were still frowned upon, neither encouraged nor appreciated. Smaller publishers were as bad, and generally worse. Then, if the manuscript was accepted, most of the editorial work was done through the mail. I remember with my first novel that alterations asked for (which I did) crossed in the mail with a letter telling me that the original was now acceptable and to forget the re-write.
My first novel was accepted "over the transom" , which meant I had sent the whole thing to the publisher un-requested. It plopped through the transom into the slush pile and was accepted. This still pleases me.
I have had other manuscripts requested within a couple of days, and have had them ultimately rejected. Speed of an expression of interest is no guarantee of acceptance. But I do -yes- check my email (even this afternoon) with a degree of anticipation.