Identify the design basis
Find the drawings, report or other agreed detail supporting the price. Clarify who provides engineering and what must happen before construction begins.
Compare excavation and water management
Look for removal limits, soil handling, drainage details and discharge responsibilities. These items can change the scope substantially even when two walls look similar from the front.
Compare the surrounding work
Fence removal, paving, planting and access protection should be explicit. A wall-only price may leave substantial restoration to the owner.
Plan for unknown conditions
Utilities, buried material and concealed wall conditions may not be established until access. Ask how additional findings are documented and approved in writing.
Photos help start the review. Access, concealed conditions and required professional review can change the construction scope.