Question for you all. I picked up Jenassa at I think level 16, and am currently on 22. At what level should I try and reset her as I don't plan on using anyone else for about 90% of this file, and should I keep trying to reset her every X amount of levels?

This was fixed a while ago in an update. Followers should level up with you now *unless they broke it again*, but remember that they also have different level caps.

Supposedly fixed.

Mostly I don't use followers, but on the occasions that my character does (had an illiterate Orc once, so any skill books he found were not supposed to increase his skills, but he did want to learn so his follower picked them up) I used the Wabbajack every 5 levels.