Surface preparation and concrete repair
This is the part of the job nobody sells and everybody should ask about, because it is where coating failures come from.
Diamond grinding
Concrete has to be mechanically profiled before a coating will bond. Diamond grinding removes old coatings, laitance, and contamination while opening the pores of the slab. Acid etching is the shortcut version and it is not equivalent.
Crack and spall repair
Cracks get chased out and filled with a polymer repair material. Spalled or pitted areas get patched and leveled. A coating applied over an unrepaired crack will telegraph and eventually fail at that line.
Moisture testing
Slabs on grade, and basements in particular, can push moisture vapor up through the concrete. That vapor will delaminate a coating from underneath. Testing is straightforward and a moisture-tolerant primer solves it, but only if someone checks first.
Dust control
Grinding produces enormous amounts of silica dust. Contractors should be running HEPA-filtered vacuum systems attached to the grinder. It is both a health issue and a sign of whether the crew is professional.