@rorygrabowsky I use lower resistance (1 to 3 on a scale of 10) when I just want to get mild exercise and it is kind of like a warm up or an easy outdoor bike ride. I use the higher resistance 5 to 8 when I'm trying to build more strength and help with the cardio. I'm not sure there is any correct answer here. It depends on your current health and what you like to do (in my non medical opinion) 😊 Here's some information on the topic...

Exercise Bikes: Resistance Vs. Duration: https://www.livestrong.com/article/552542-exercise-bikes-resistance-vs-duration/