Walmart, Never, My other truck which I had bought new in 1990 I changed the oil every 7000 miles by myself from new. Then one day I got lazy in 2002 the first and only time I took it to walmart and they cross threadded the oil drain plug
and when I noticed it I took it back and said sorry, however I had to purchase a new self tapping drain plug and fix it. I told them off. Yes they offered to fix it but I told them that since they could not do a smple oil change with out screwing it up how could they fix it with out making it worse. One of my jobs when I was in the Air Force was working in the lube rack, I changed oil in everything the AF had for 1 1/2 years aprox 10 - 20 per day and never had an issue (at least with a normal passenger car or truck) Heavy equipment thats another story. Sorry walmart have a coke and a smile.