I have personally paid for private testing of Tirz vials from SRY and ASC (and posted the COA's here) and been involved in group buy testing where I a always volunteer to to be a vial donor on group tests. When you are vial donor you are then 100% certain that your batch has been tested. I also pay for testing of a variety of peps (many that I don't even own) on a popular group test server. This isn't to say that I test everything. I have pinned plenty of vials without testing first.
Anything I am putting into long-term storage I want to make sure has a good test. This can be either me paying the $300 myself, group test or third party test that I know is from the same batch (PGB or others). I may also test again when I pull the vials out of storage if they have been stored for a >1 year. I bought most of my hoard in October so I have some time to make this decision.
Peptide Test is in the process of setting up a group test system where one person sets up the test and then participants log into PT to pay their share, vial donors send their vials directly to PT. The results are shared back to the group. I think this is a great idea, 3-4 people can choose to create their own private group test very easily and it reduces your test cost to $100 or less (depending on the number or people and number of vials). I think the test cost is like $300 plus $100 for each additional vial from the same batch.