A Farmington roof replacement includes the layers below
The shingles or metal are the exposed covering. The deck provides the fastening surface; underlayment helps protect below the covering; flashings carry water past walls, valleys and openings. Those parts have to join correctly for the new roof to work as an assembly.
Removing old material gives access to the deck. Soft or damaged wood needs to be restored before the roof is closed. The proposal should explain how decking beyond the visible allowance will be approved and charged, because a surface inspection cannot reveal every covered board.
Ventilation also belongs in the replacement discussion. The attic needs a suitable intake and exhaust arrangement, with a clear path between them. Adding a ridge vent alone does not establish that the system has the air entering below to support it.