Most summer breakdowns are slow failures nobody checked
A system rarely dies on a mild day. Capacitors weaken for months, coils load up with the fine dust and pollen that drift through Cypress, and the condensate drain line grows slime until the pan fills. The first sign most owners get is the hottest afternoon of the year, when a part that was already marginal finally quits.
Spring and fall are when these problems are cheap to catch. A coil you can see light through, a capacitor reading in range and a clear drain line cost you nothing in comfort. The same three items found on a 100 degree weekend mean a hot house, an emergency call and sometimes a wet ceiling.