Said it before & I'll probably say it again - THE best thing you can do for your piston-prop aeroplane is buy & fit a JPI or equivalent all-cylinder monitor. Agree 120% with bev 666 re John Deakin also - use SCIENCE and factual DATA rather than sad old wives tales to run your aircraft.
I've been able to tell the LAME that the lower plug on No 3 LH Eng is knackered, before it started costing money; and that an exhaust valve was sticking on the No 4 before it belted a hole in the piston. Those 2 examples paid for the device; let alone the benefits available if you also fit GAMIs and choose to run LOP (how about a 20 LPH per side reduction in fuel consumption at the same cruise speed and temps as at 100 ROP?)
Another OWT - reducing power just after take off. It is a BAD idea. Piston prop aircraft have an enrichening system in their throttle setup (both carb & Injection) so at full (take off) power, extra fuel is delivered to aid in cooling. By reducing power immediately after take-off, you are INCREASING temperatures and making the engine work harder.