Back when I was doing basic pedagogical training (you know, when we baked our syllabus onto a clay tablet), one of the strongest suggestions was that every time we give an assignment, before we give an assignment, we take the assignment and write it ourselves (this was in the context of an English department, so the assignments didn't involve other production than writing).
At various times, I've done this pretty regularly. At other times, not so much.
But I've found for certain kinds of assignments, it really helps if I do them, and then give my work to the whole class as a model.
This semester, for one of my classes, I've adopted a discussion leading assignment from a really smart colleague. However, I was a bit late getting students to sign up, and even though I offered to move the first one from tomorrow to a week from tomorrow, everyone asked not to do it. So I moved it back to tomorrow and did it myself.
First, I have to say, it was good in a good way; you really have to put in some real effort to do a good job, and have to read carefully, and that's good.
It took me about 5 hours to do, and that's after having thought about stuff this semester and such. So I started with an advantage there.
On the other hand, the students get to work in small groups to help each other, and I didn't get to work in a group to get help, so that's perhaps a small disadvantage.
What's really good is that I was able to tell the students (in an email) how long it took me to do, and to encourage them to give themselves plenty of time as they work on the project (it counts for a fair chunk of their grade, so I don't feel bad if they put in a like number of hours).