Correct AC sizing determines whether your 20 year old unit deserves repair investment
https://precisionhvacrepair-after-hours-sac-near-university-park6171.urbanvellum.com/posts/coolant-chemistry-determines-whether-your-unit-survives-15-or-20-years
Whether a 20-year-old AC unit is worth fixing depends largely on whether it was properly sized for your home in the first place. An undersized or oversized system will waste energy and fail prematurely, making repair decisions unreliable