Check service technician accreditations, experience with different fibers and tile types
https://aged-wiki.win/index.php/Tile_and_Carpet_Cleaning_Services_Checklist:_From_Grout_Cleaning_to_Deep_Steam_in_St_George_39782
Check service technician accreditations, experience with various fibers and tile types, and training on stain removal and grout sealing.