Questions that you should be asking before hiring a retaining wall contractor:
Do you have Liability and Work Comp? Ask for a copy.
Will you put grid in the wall? (3’ tall and higher) then ask what kind of grid, to see if they know. If they are experienced, they will know.
What type of compaction equipment will you use? (Should be using equipment of some sort, like a Plate compactor, a Jumping Jack, a Sheepsfoot compactor)
Grid and compaction are key. If they aren’t planning to use them or don’t know how to correctly install them, your wall will likely fall down. We see walls that were recently built but have failed because the contractor did not know what they were doing.
Will you use rock behind the wall? (If the answer is no or not much, you should not hire them. Period.)
How do you construct the footing? (Should be 6-8” of Compacted Rock depending on soil conditions)
Will you warranty your work? If so, for how long? Warranty in writing?