Ask Daphne! What’s the timeline for following up?

Stylish zebra shoes to wear whilst waiting for Lisa from Chicago, who writes:

I have a dilemma that’s new to me, regarding when (or whether) to make a status query about a submission. Many moons ago, I sent a query to an editor at a major house, and 14 months later, I got a nice note saying I should send the manuscript, and apologizing for the delay in responding.
That was in March (2008), and I turned it around more or less immediately and sent the manuscript on April 1st. I have heard nothing since, and am starting to itch a little — I’m sure you know the feeling. Now if this were a novel, I don’t think I’d worry yet. But it was an easy reader of about 250 words. I know the decision making process can be complicated, regardless of how short a piece is, but still, I worry about things like: Might there have been a piece of chewed gum on the envelope next to mine, and did my submission get permanently stuck to a really crappy manuscript that she scrambled into a ball and lobbed into her garbage can, shouting “SCORE!” Well? It could happen…
OK, what do I do — make a status query now? wait a couple more months? Since it was requested, I don’t have any sense of an “appropriate” wait time.

So basically, it’s been five months since you sent a requested manuscript, and you already know that this editor may be slow, but she does eventually get to her pile of reading (as evidenced by the 14 months it took her to respond to your query).
I know the impetus to imagine the worst is a common one, but the truth is, we’re all just snowed under by the amount of reading to be done. I would send her a short little note (or email) with the gist of “I’m just checking to confirm you received my requested submission of April 1st of ______(title). I look forward to hearing your reaction.” And then get back to work writing your next book. Good luck!