Large projects benefit from a room-by-room condition check
Walk the house with the bidder and identify painted popcorn, stains, cracks, tall ceilings and areas with previous repair. Those conditions can affect labor more than a simple total square-foot figure.
For occupied homes, discuss whether bedrooms and living areas can be completed in sequence. A good phasing plan can make a whole-house project much easier to live through.
Specialization does not eliminate the need for a detailed scope
Even when a company focuses heavily on popcorn ceilings, confirm exactly what the price includes after the material comes down. Skim coating, sanding, primer, final paint, fixture handling and cleanup should be explicit.
If the material's composition is unknown, resolve testing before disturbance. No amount of removal experience makes visual identification reliable.