I was at Discount Tire this week peering through the visitor's window watching their guys work.
Things that really stuck out:
1) How fast the guys work
2) Ill placement of floor jacks
3) Not using jack stands
The Silverado in the picture below was supported only by 4 floor jacks and sat like that for about 2ish hours. I'm sure they have their floor jacks serviced frequently but surprised they didn't at least stick two jack stands under the frame...just in case.
I know on this forum you would feel the wrath of the members if you didn't use floor jacks.