What may point toward a repair
An isolated defect, a membrane in good condition around the affected area and a sound deck may allow a targeted intervention. The repair must be compatible with the existing covering. Ask what caused the problem, which area will be treated and how connections will be checked.
What may point toward replacement
Repeated leaks, multiple damaged areas or wet components may justify a broader assessment. Age alone is not enough to decide: history, maintenance and actual condition matter. Replacement also provides an opportunity to assess insulation, slope and details that a surface patch would not address.
Compare two scopes of work
Compare inclusions: material removal, deck work, insulation, membrane, flashing, drains and waste disposal. Ask about exclusions and how discoveries after tear-off will be handled. A total price alone does not explain the difference between proposals.