How long after being separated should I be expected to set my ex wife's alarm clock for her because she still doesn't know how?

As soon as you part ways.

For as long as you continue to do it. You're setting the rules and the expectations now. Some might say she's taking advantage, but on the other hand, if you remain kind and helpful to each other, it's much easier to co-parent.

zero minutes.

When my ex and I were still married, he would just say "I'm going out," and then be gone. I figured I knew where he was going, but it really didn't matter anymore. There was nothing much to do but accept it. After he served me and I found out about his fiancee, it was a little surreal, but the weirdest moment was when he said, "I'm going to go meet up with so-and-so tonight if you don't mind." I remember thinking, "If I don't mind?!? WTF? You didn't ask for permission to go out with her before you served me with papers. Why the heck would you ask about it now? Of course I freaking mind." But, instead, I just said, "Nope." I mean, what else are you going to do? Sure, you could make a big stinking deal about it, but it doesn't help. When the relationship's over, it's over. You have to push past all that and do what you have to do to remain civil for the sake of the kids. Sometimes, that means setting an alarm clock for someone when you'd be happier chucking it at their head. 

Sometimes, the only thing that keeps me in check is remembering that I have to co-parent with my ex for at least 13 years, but we'll be in each other's lives forever. When I'm mad, I just ask myself if it's worth straining the relationship for 13 years over the alleged offense. It never is.

you're welcome. sleep well. =)

O_o

What?  Do you drive to her place and set her clock each night?  Wow!!!!  Wackadoodle extraordinaire!!