The custom courses do not expire. The best place to find your answer is within your club. There are many ways to use a custom course and the owner or tournament director usually have a plan. I know in our club the directors and owner are the only members who can create a custom course and it is talked about before one is set up as to the way it will be set and used.
I'm sure the owner of your club has a plan and will share the way he uses them if asked.