Before the hot months. Florida asks a lot of an air conditioner, and the failures tend to arrive the first week it really matters. A spring check-up finds the weak capacitor or the clogged drain before it becomes a no-cool call in July.

After buying a home. A home inspector will usually confirm the system turns on and blows cold air. That isn't the same as evaluating it. A check-up tells you the age, the refrigerant type, the actual performance, and whether you're looking at a system with ten good years or three.

To protect a manufacturer warranty. Most equipment warranties require documented annual maintenance, and a claim can be denied without it.

Before a rental or a season. Landlords getting ahead of a tenant turnover, and seasonal residents wanting the system checked before they arrive or after the house has sat closed up

After a power event or storm. Surges, outages and flooding can leave damage that doesn't announce itself until the system is under load.

When the system is older and you'd rather plan a replacement on your own schedule than during a heat wave.