Create a specification for each opening
Do not assume the second door has the same dimensions or hardware because the frontage looks symmetrical. Record the selected model, finish, window layout and opener decision by opening. This prevents one door’s measurements from becoming an accidental order for both.
Discuss future matching honestly
A finish or model available now may change before the second phase. Ask what can be reserved or documented, but do not treat a current product sample as a promise of indefinite availability. Existing weathering can also affect a later visual match.
Keep project records separate and connected
Each phase should have a clear work scope and any required approval records. Maintain a shared design plan while identifying which opening has been completed. Access arrangements may also differ while one garage bay remains in use.
Your questions
Can both openings use one measurement?
No. Each opening needs to be checked for fit, clearance and the selected assembly.
Must both openers be replaced at the same time?
Not necessarily. Evaluate compatibility and condition for each opening, then state any retained equipment clearly in the proposal.