On Monster Rancher 3 how do you get your monster to stay alive for a long time?

To keep your monster alive for a long time in Monster Rancher 3, focus on maintaining its health through proper training, balanced meals, and regular rest. Ensure that your monster's fatigue is managed by not overworking it and providing adequate downtime. Regularly visit the doctor to heal any ailments and monitor its happiness levels to prevent stress. Lastly, choose the right type of training that suits your monster's breed and capabilities to enhance its longevity.