I fly a PA28 180, and the POH is not all that great when it comes to leaning. Full rich below 5000' then basically as required. I am an Iowa flat lander, so for the most part DA is not a huge issue unless we have a really hot day. SOP is lean for taxi, full rich for TO, lean as required above 5000', ROP for cruise. I recently flew to AMA and took notice of the higher DA and leaned for best performance on TO...then continued to lean through the climb to cruise, balancing EGT, RPM, and CHT temps. Always sacrificing climb to maintain a CHT at or below 400 on my hottest cylinder. Performance was outstanding, especially climbing past 070 through 110, and I have since been doing that on every flight. My question is this....from a mechanical stand point, is this practice harming the powerplant in any way? As I said the POH is crap for information on this, and I don't need to be buying a new engine any earlier than TBO.