What I do: drive the car onto level ground; put a magnetic level (magnetic = just so it stays in place when you drive home) on the truck somewhere, adjusting it with shims so it reads level, maybe masking tape it in place if needed; drive into my driveway, backing in since it slopes down; jack up the front of the car until the magnetic level reads level. This way I know the vehicle is as level as the ground was when I set the level in place.

Actually, I did that the first time, and made a note of the jack stands so I can just replicate that. Or if I have any doubt, I can just go back to the original procedure.

From checking roof, hood, side skirts, frame, etc. I think I concluded that NOTHING on the truck is level, which is why I went with the above method.

BTW, my driveway slope is about 4 degrees, which is just about perfect for working on cars - not enough to be dangerous, but enough so that things are pretty level when the lower end is jacked, and also I just need wheel chocks on the downhill side.

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2001 X5 3.0i, 203k miles, AT, owned since 2014