Have you read "extending the oil drain interval beyond the OEMs' should only be done with a uoa support program"?
The uoa will tell you when the additives are depleted and/or the oil is out of grade one way or the other.
An ISO particle count is for systems that might hold 30,000 gallons where changing the fluid out early cost thousands of $$.
"Wear metal" count is for identifying little problems before they become break downs and expensive repairs.
Phyical properties identify water, fuel, glycol, chemical, bio contamination and viscosity.
Some would advise to "crack a book".
edit not you Z, the post ended up here.
The uoa will tell you when the additives are depleted and/or the oil is out of grade one way or the other.
An ISO particle count is for systems that might hold 30,000 gallons where changing the fluid out early cost thousands of $$.
"Wear metal" count is for identifying little problems before they become break downs and expensive repairs.
Phyical properties identify water, fuel, glycol, chemical, bio contamination and viscosity.
Some would advise to "crack a book".
edit not you Z, the post ended up here.