Hertz Donut

Whenever I'm under a car I have jack stands, spare wheels under the rockers, and a trolley jack backed off just enough to relieve upward pressure (location depends on what I'm working on). Ideally I'd have a hoist but we're renting while we look for some land so that's not an option. I'd rather be called a paranoid pussy than "the late Mr Donut, who leaves behind his wife and two children."

Having said that you also need to know when to back off on what you're trying to achieve. I almost didn't notice my old car moving sideways one day when I was trying to force a particularly stubborn Panhard rod back into place. Thankfully I heard the stands start to rattle a little as they leaned to one side so stopped what I was doing, got out from under the car, grabbed a drink and gave myself a good hard mental uppercut.

rpg51

I've been using ESCO stands. They seem pretty solid. Not cheap.

One thing that can cause real problems is attempting to raise a car when you are not on a good solid concrete floor. Even asphalt can cause real problems because sometimes it is quite soft.