I won't rewrite everything John Deakin has written but there are many 'old wives tales' around. Running leaner than peak is not dangerous in any way if the engine is smooth the CHTs drop visibly. The hottest point is around 50° ROP where you will have the highest CHTs. This is exactly where some POHs recommend you cruise. Why? Maybe the marketing department had their say (more range, more speed, less engine longevity but that is not the concern of the marketing department).
The average PPL is very much undertrained on engine management. If you are an owner, you should be extra motivated since you pay the bills for fuel, maintenance and engine care. I fly LOP or at peak since 1996 or thereabout. At the current fuel prices, the savings on fuel alone pay for a decent engine overhaul at 2000 hours with money left over for other goodies.