A house rule that we in as the staff of Manchester at Midnight have decided that in order to have a 5 dot in a skill (And some merits) you need to spend a minor DTA to maintain this level of skill.
Ideally, having a 5th dot in a skill basically means that your character is at the peak of human ability at that skill. Getting took a lot of time in your character's life (Or unlife). However, maintaining such a level of skill requires practice to stay at peak performance. Athletes train in gyms, EMTs attend refresher courses on medical knowledge, even thieves pick locks over and over again to make sure they can when they need to.
When making your DTA post to your character manager you need to note what skill your are keeping up and how you're going about doing it. It doesn't need to be a lengthy description explanation but something of worth.
Example: "Frank Mason wants to keep up his sword fighting skills, Dave Whittenburg and him spar in the basement of Elysium a few nights a week. spending a minor DTA."
Or
Example/Shameless advertisement.: "C-J wants to keep up his shooting skills and visits a local firering range called the second amendment. After squeezing off a few hundred rounds, he feels a lot better about his skills."
You only need to spend 1 minor DTA per skill per month. If you have multiple skills at their 5th dot, you'll need to spend 1 DTA per skill.