I am jumping in with my opinion - and my practices.
I do not test. I do not believe every COA posted by these manufacturers. I mean, c'mon, we already know their tactic of using attractive women as avatars for their "reps." Oh, and calling us "dear" or "honey."
These companies are making a shit ton of money off of selling us "testing and research products." I do not for one second believe that each order sent out is meticulously plucked from the same batch number. I'm pretty sure my recent purchase of a Reta 60mg kit contains vials from several, if not all, different batches.
Call me dumb. Or call me lucky. I have not had any bad experiences with my products. They have worked as intended, with the potency indicated on the kits I purchased. However, I barely had the funds to even purchase gray (the economy and recent life situations,) let alone having the money or want to waste any of my kit getting a test done that does not reflect ALL of my kit.
Testing can give reassurance, sure, and it is great that some companies are honest about their tests and give us those results. With AI running rampant and making it easier to use to deceive and obfuscate data, I take those results with a grain of salt.
Now...I know I SHOULD be filtering. I have no excuse as it is fairly simple and inexpensive.
But, as far as testing each time I order some peps, naw, for this guy - it ain't happenin.