I am not sure which gauge they are using but I have always used this method and checked myself.

On a side note every time I go to get an oil change they find something they would like to replace- often prematurely. This could just be my oil change place though- I doubt they are all this way.

@Dog: Thanks for your answer, and for the Link!

Tire care is so underrated! Tires affect every aspect of your driving, and in turn, your safety. While I agree with @Dog that you can’t always trust what people at a quick-lube business will recommend, if the tread on your tires is wearing thin, they should definitely be replaced.

@jeffgoldblumsprivatefacilities Agreed!

Buy yourself a tire tread gauge. They cost about $10 on line. In most states, it is legal to run tires down to 2/ 32 inches. I usually run mine down to 4/32 and then buy a full set. If you rotate religously, the wear will be (almost) uniform.

Another good reference is a US penny. From the top of Lincoln’s head to the edge of the coin is 2/ 32 inches. I would not trash a tire that still has 6/ 32 inches of tread. Of course, I have no idea what scale you refer to in your question, 6.2.

@UScitizen Great idea on the tread gauge. I did not know such things existed! The 6.2 was printed out on the sheet I received from the quick lube shop where I got my oil change. I see I have a lot to learn about tires! :-)