Establish the equipment history
Look for an installation record or ask a contractor to interpret the model and serial information. Note past repairs and changes in comfort or reliability.
Make the comparison specific
Ask what useful result the proposed repair is expected to deliver and whether replacement would address a documented limitation. A lifespan estimate is not a warranty or an assessment of your unit.
Take this question into the conversation
“What did you find, what will the proposed work solve, and how will we know it worked?”
This is general educational guidance, not an assessment of your equipment. A qualified contractor must evaluate the actual system.