The question of how many minutes a day you should rebound is one that does not have a definitive answer. The amount of time you spend rebounding will depend on your individual goals and needs.
If you are looking to improve your overall fitness, then spending 20-30 minutes on a rebounder each day is a great place to start. This will give you enough time to get your heart rate up and break a sweat, without overdoing it.
If you are trying to lose weight, then you may want to increase the amount of time you spend rebounding. A good goal to aim for would be 40-60 minutes per day. This will help you burn more calories and fat, while also improving your cardiovascular health.
Finally, if you are using rebounding for rehabilitation or injury prevention, then the amount of time you spend will be dependent on your specific situation. Always consult with a doctor or physical therapist before starting any new exercise routine.
At the end of the day, the best way to figure out how much time you should spend rebounding is by listening to your body and finding what works best for YOU!