3-Be sure you have proper expansion joints / breaks ever so often to control where it cracks. Most all concrete will crack over time, you want it to crack in the joints not random
True. I learned a long time ago that there is one guarantee with concrete, it is guaranteed to crack.
FWIW, I have the best luck with flat work using 1/2" rebar, 5000 lb rated mix, and fiber added to the mix. This would be for residential driveways and aprons. If an owner is driving a large truck or parking big weight on the slab, I will add in page wire and place a 6" slab.