Should I buy materials myself or let the contractor source them?

Buying materials yourself can save 15–25% on contractor markup but transfers risk to you — wrong quantities, damaged shipments, and warranty claims become your problem. Best practice: source ONLY the high-markup items yourself (tile, vanities, faucets, light fixtures, appliances), and let the contractor source consumables (drywall, screws, grout, paint, mud). Coordinate delivery to land BEFORE install day — a missing case of tile on hour 1 of a $4,000 install day blows the whole schedule. Get the contractor's exact spec list in writing before you order; even minor differences in tile thickness or backer-board choice cascade into rework costs.