Yes, it matches up with miles driven, not related to the time going by.
One question is that, before I took my car to the shop for Valve Cover Gasket changing, my car can run 600 miles/quarter oil for about 1 year. But right after they did their job, it came into 200 miles/quarter. Did they do something bad to my car? I don't think it can change so fast for no reason.
Now I am 90 percent sure it is burning oil. The thing is I have not done any mechanic job myself yet. it is that possible for me to check worn valve guides or leaking valve seals?
Thanks a lot for you guys' help. I really learnt a lot.