I've recently created 2 plans for 2 friends who are newer runners (a 1/2 marathon plan and 10 miler plan) and love doing it. It makes me feel good to help others with something I love so much. Obviously, I do this with the caveat that I am not a coach.

Anyone else do this for others? (Either as a coach or a friend?)

I coach HS XC and do all of the off season and summer plans for the kids.  The biggest problem with HS age runners is they want to do all runs at the same speed and distance.

I've done a couple of "suggestion" plans for people (including DW) who want to move from marathons to ultras.  I'm careful to tell them it's a guide and should be flexible, as what works for me might not work for you.

I am a PT Leader at work (USAF) and also known as the crazy guy that runs a lot. So...naturally that makes me the expert in devising running plans for our unit members that are on the bubble or failing their PT test. I don't mind doing it when someone comes to me and asks for help. It is the first step for the person to show me they are motivated. But I don't like doing it because it is required by leadership. In this case, the person usually isn't motivated and will give it up. Of course, we have ways of motivating them; however, that is usually limited to just getting them on the track. I can't force effort.