The sooner you start the better, I’ve seen binders going back several years that cover the entire life of an engine. You give them relevant info so that they can make informed decisions and provide accurate feedback, and change over change you can see the lifecycle of your engine change, as bearings wear or contaminates are introduced (coolant, fuel, etc…)
Certain parts of your engine are made out of certain materials… so if they see elevated amounts of aluminum it can be x,y, or z. If it’s copper, zinc, whatever - it is something else.
You do not send the filter, but opening it up yourself for visual inspection is always good. Too much sparkle or large pieces, you can skip the Blackstone and just rebuild, lol.
The report helped me identify a failing wrist pin button (cover) on my friend’s plane. There isn’t a lot of aluminum in those engines, and as I was tearing it down, one of the buttons was much worse than the others, minor scarring in the cylinder, so we did a top end rebuild. There were trace amounts material in the filter of a nonferrous metal, but the Blackstone was conclusive and helped with the diagnosis. They also had a several year history on the engine which pointed to the fact that this was a new issue.