You don't need to be operating LOP or have all-points monitors to gain value from understanding your engine properly. I largely operate low powered carb engines, but have gained a great deal from the writing of Deakin etc.
When teaching a student about leaning I can tell them how it actually works rather than the usual "leaning too much destroys engines!" that I got when I was learning. Likewise why the engine runs rough when you lean aggressively, that it's the leanest cylinder falling off the HP curve, not the engine detonating (as many instructors I know believe).
With that said every time I fly my little O-235 I'm running LOP. If I lean till rough then enrich till smooth the leanest cylinder(s) are likely LOP, possible with some others at peak or ROP. Which is why I laugh when people say "You can't LOP without the equipment!". True I can't climb LOP etc, but how to do I know where each cylinder is on my horrible EGT spread? And unless I'm at high power settings it doesn't matter. Considering the POH tell me to operate it at the worst EGT it could it's not like things could get any worse is it?