I also practice it on my 21 year old engine, my oil generally lasts several years with todays low sulphur fuels, and in spite of the tired hacks in magzines repeating the same old rubbish they first read themselves years ago about oil going acidic after a few hours use and how your engine will corrode away before your very eyes, its is water contamination from condensation that is the deciding parameter.
I have found it is not necessary to pay our for a formal lab test every year, a simple DIY viscosity and test tube sample will tell you all you need to know.
All this is still far too novel and rocket science for most people. I can understand that and as long as the scribes in the magazines continue to peddle such out of date rubbish I guess things will not change.
You pays yer money and live by yer decisions etc etc