Right now, I'm waiting on responses to over a dozen submissions I have around the traps. Three of them were submitted last year, one of them to a famously slothful (though fantastic) market back in October.
While I don't fault any market for the time it takes them to do business, I feel like good stories are going to waste sitting dormant like this. And since many markets aren't receptive to simultaneous submissions it can be a juggling act. Does one let the piece languish on the slush pile in the hopes the market will eventually reply, or does one suck it up and send it out in hopes it might find another home quicker?
Querying is always a fine line to walk. How early is too early? Has the market gone into hibernation or closed down for some reason (check their blog or Twitter feed, Ralan's or Duotrope)? Has the submission been lost to the spam gods? Always be cognisant of a market's response times (Duotrope's submission tracker is excellent for this) and act accordingly. One wants to retain a good professional relationship without seeming too pushy, but once a submission hits the four, five, six, seven month mark, goes well past the allotted response time, it might be time to drop a polite note to the editors.
And I mean POLITE. One does not want to be the type turning up on "Slushpile Hell" or an editors blog as that sort of writer who thinks the editor or agent owes them something. Love your word babies, but don't love your word babies.
And while you're waiting, go write something even more awesome. Try not to hit refresh on the email inbox every five minutes. No, I don't do that at all some days...
Ah, but here is me, one famous for impatience, lecturing on patience. The business of writing can seem like a lot of hurry up and wait, and when it happens it all happens at once. "Where has your genius been for so long!" they will say, and the reply will be "plugging around the markets for years". Who can tell the when the vagaries of the art and market will point it's Eye of Sauron on one writer or another.
Just keep plugging away. Practise practise practise.