The deck is the roof
Shingles are a wear layer. The structure doing the actual work is the decking underneath, and it is the only part of the assembly nobody sees between one replacement and the next.
Soft spots around chimneys, in valleys and along the eaves are normal on a roof at the end of its life — those are the places water has been sitting. Replacing a few sheets while the roof is stripped is a small line on the quote. Discovering them at the next replacement means the layer you paid for was never nailed into anything solid.
Ventilation is not an upsell
Air has to enter low and leave high. When it cannot, moisture from inside the house condenses on the underside of the deck through the winter and heat builds under the shingles through the summer, and both shorten the life of a roof that was installed perfectly.
The common fault is exhaust without matching intake — ridge vent added, soffit intake blocked by insulation or never cut. The system then draws its air from the house. Balancing it costs little while the roof is open and is awkward and expensive afterwards.
Flashing is where roofs actually leak
The field of a roof rarely fails first. Leaks start where the roof meets something else: a chimney, a sidewall, a skylight, a valley, a plumbing stack. Those junctions are handled by metal, and metal has a service life of its own.
Reusing old flashing and sealing the gap with caulk is quick, it costs almost nothing, and it is the reason for a large share of the repairs we are called to. Caulk is a maintenance material, not a flashing. New flashing goes on with a new roof.
Choosing the covering, honestly
Architectural asphalt suits most houses and is what most replacements use. Impact-resistant shingles are worth considering where hail is a recurring problem rather than a one-off. Metal costs more up front and lasts substantially longer, and it suits some rooflines far better than others.
A low-slope section — a porch, a dormer, an addition — is a different assembly from the steep roof next to it and must not be shingled as though it were. Where a roof mixes pitches, it gets more than one system, and the quote says so.
