Thanks for the quick replies! I just wanted confirmation as it is little daunting to be a newbie with no experience. I definitely change gears based on how I feel. It is just frustrating when someone tells you it is still the wrong gear. Even with no experience, I still know how I feel better than he would know how I feel. To answer your question, he tells me to use the smaller gear because the bigger gear takes more power and will cause exhuastion. It has nothing to do with the cross chaining. He has taught me not to do that so I try to refrain from cross chaining. I say the little gear causes my legs to tire quickly because I have to have a much higher cadence to keep the same speed. To me, it's like sprinting! And if I don't feel exhaustion on the big ring, why not use it? It just FEELS right to me.