We put the effort into the base
Most shortcuts in concrete get taken in the base, because nobody sees it once the slab is down. A base that's only raked level settles with the dirt, and the slab sinks and cracks with it. So we dig out the soft ground and pack the base before the forms go up. We also check where your water runs, so a slab doesn't end up falling toward your house.
When a budget gets tight, the base is usually the first thing people want to cut. That's the one I push back on. I'd rather shrink the slab or keep the finish plain than pour a nice surface over ground that's going to move, because a plain slab on a good base usually outlasts a fancy one on a bad one.

