Measure both sides and the top and identify whether one face or both are included. A doorway may have different trim on each side. The quote should describe the actual surround instead of assuming one opening means every adjacent decorative surface.
Agree filling, joint preparation and the painting boundary. A primed replacement can still need final decoration after fitting. Window glazing, specialist seals and rated-door certification are outside the task even where the new architrave sits beside those systems.
The base of an architrave often meets skirting of a particular thickness and shape. Include that junction in the enquiry. Replacing one trim element may expose a mismatch, but changing the entire room’s skirting is a separate decision and scope.
Replace the accepted ordinary decorative surround with suitable joints and fixings, leaving the agreed preparation for finishing. Scope limits: Ordinary decorative surrounds only. No structural jamb or opening modifications, specialist glazing, fire-door certification or hazardous-material disturbance.