Video Game Time Token reward sytem

We had a problem with too much video game time, not enough motivation to do anything other than video games with the kids. We have implemented a token system. Each day they are awarded a 30 minute, 15 minute, or 5 minute token based on their behavior for the day. We pay out the prior weeks tokens at the end of each week which each kid stores in their bank until they want to cash it in for screen time. If they want additional screen time they will have to do chores to earn that time, we rewar