Points Limits gives you the ability to configure points earnings limits to limit the amount of points your users can earn.
You can configure different limits per points type and limit the points earnings by lifetime, per day, per week, per month and per year.
In addition, this add-on has the ability to configure different points limit per user role.
There is a list of all available demos for this add-on:
In case you need, all features and possible options can be found also on the add-on documentation.