No need to judge good or bad about engines and warm ups.
As the efficiency of the engine designs improved over 50 years, the clearances over the blade tips needed to get tighter. Unfortunately differences in thermal expansions between parts works to defeat the exactness of this clearance either too little and it rubs causing permanent wear. While too much and the efficiency and/or stability goes to hell.
Be kind to your engine and follow the instructions that came with it
