I think it's important in any discussion to define the terms and talk about the same things to avoid misunderstanding. By that I mean for example when someone suggests gas oil mix ratios of 50-1 or 100-1 we're definitely not talking about the LawnBoy oil in the green can. Don't do this.
Sometimes, people will talk about running "lean" when referring to 50-1 or 100-1 gas oil ratios. This is incorrect. Gas and oil mix ratios in different proportion do change the air fuel ratio, but not the way people often think. More oil means a leaner air fuel ratio by definition. Regardless of the mix ratio it is important to adjust the carburetor for (relatively) clean burning. This is important and it is usually ignored or at best misunderstood. The manuals will usually say something like "1.5 turns out", this is the starting point, so it will run, and not the end point. It will be extremely rich. The altitude needle as it was called is actually a precision adjustment and the correct set point varies depending on temperature, and gas oil mix ratio. Jetting also plays a role. What I've seen in the past is that a typical 2 stroke mower received indifferent maintenance or tuning, was fed a heavy diet of oil in the gas (a little "extra" must be good too, right?) and a mistuned carburetor - will exhibit lots of smoke, fouled plugs, heavy sludge in the muffler and eventually through long use, stuck rings and scored cylinder walls.
I purchased a "Krylon Rebuild" mower that exhibited all these features, and more. The needle bearings were just about done for, and it was fortunate that I rebuilt it when I did as I suspect it would not have made it through another season without a failure.
This makes 3 seasons on the rebuilt engine, this winter I'll pull the jug and take some pics and we'll see what a steady diet of 100-1 of a modern high tech oil does. I will say the classic LB muffler sludge is much improved, and importantly the exhaust ports stay cleaner.