I'm still learning how to teach; I haven't been doing it that long. However, I've been eavesdropping on teachers my entire life, and especially over the past several years I've been absorbing policies and integrating what makes sense to me and disregarding the rest, which is what you have to do: You have to figure out what makes sense for you, based on your own personality and teaching style, and that can take a number of years, based on what you teach and where (geographically and age-wise). Because my parents are teachers, I've been talking to them about their own policies, especially my mother, who teaches German and French. Not that non-humanities teachers can't incorporate similar policies, of course, but many of the topics covered are the same, and that can affect how you teach. At least, I think so.
Right from the start, I've incorporated a policy that disallows an acceptance of late work. That's to say, I just don't accept it. Partly it's because I don't want to have to keep track of who's handed in what, and partly because I want my students to learn discipline. They may or may not go on to careers in which deadlines are extremely important, but there's no way for either them or me to know that now, so I go on the presumption of the worst case scenario: that they may have jobs that require something very important being done at a specific time. Obviously the world isn't going to collapse if they don't hand in a paper on time; the worst that will happen is that they fail a class and have to repeat it (although I did have one student tell me, the first semester I taught, that because he failed my class he wouldn't be accepted into his desired degree program).
The caveat is that I do actually accept late work, if the student comes to me beforehand to let me know what's going on. However, even as recently as last Thursday, when a first essay was due, two students spoke to me before class to tell me what their situations were, and to ask for an extension - which I granted - while another came to me after class was already underway to ask me for an extension - which I did not grant. Timing is important, and I want to relate that to my students.
And of course I do recognize that there are times when really crummy things do happen at the worst possible moment, and to punish the student for something that he can't control isn't the right way to go.
Yesterday, a student (an older woman who has already asked questions like why I can't hold on to all their drafts) in my lower level class e-mailed me several hours after class had ended to attempt to submit an essay, which had been due that class. Her excuse was that she had a family emergency and therefore had not been in class to submit her essay. I'm conflicted about this because I have accepted late work from students who have contacted me regarding family emergencies; however, they have unilaterally been in touch before class. They're are also good students: They come to class with their work prepared; they're slightly older (my age or older, just like this other student) and have jobs, families, etc., and seem to be more serious about their studies; they're in contact more regularly - whereas the student from the lower level class whines a bit more and complains about the difficulty of the writing prompts, has the wrong edition of the textbook and has asked to use mine, etc. My instinct is towards a disinclination of accepting her late work, not because I dislike her, but because she doesn't seem like a mature student, despite her age.
I asked my mother for advice, because while I had made up my mind not to accept her late work, I'm still learning how I can tell my students that I can't accept their work without making it seem personal.