Start with the vanity layout
Measure the cabinet run and note sink type, faucet holes, and wall returns. For a double vanity, bring both sink specifications and ask your fabricator how veining will run between them.
Choose for daily use
Marble brings natural veining and can etch from acidic products. Quartz offers a consistent appearance. Ask about care for the specific finish and slab you select.
Ask about smaller cuts
If the project is a single vanity, send the dimensions and ask what slab sizes or remnants may be available. Include any matching splash or shelf in the layout.