Limiting custom jutsu and weapons?

I think there needs to be some sort of limit, so that people don't constantly make more and more jutsu that they probably won't even buy for a long time. I reckon there needs to be a system in place, or maybe just restrain it to one custom jutsu a week.

I think one custom jutsu a week would be a simple and effective way to do this.

This would not include the custom's when someone is first making a character.