Baltimore summers are hot and humid, which is exactly when a weak A/C system gives up. Testing it in spring costs less stress than discovering the problem in a July traffic jam.
A/C systems do not 'use up' refrigerant
A sealed system should hold its charge for years. If cooling faded, refrigerant escaped somewhere — a hose, an O-ring, the condenser, or a compressor seal. A recharge without finding the leak cools for a while and then fails again, so we look for the leak first.
Other reasons air feels warm
A clogged cabin air filter, a failing blower motor, a blend-door actuator, a slipping compressor clutch, or a condenser packed with road debris can all reduce cooling. Weak airflow and cold-but-weak air point in different directions, which is why we test before replacing parts.
Habits that help
Run the A/C for a few minutes every couple of weeks, even in winter, to keep seals lubricated. Replace the cabin filter on schedule. Use recirculate on very humid days to cool faster, and rinse leaves and grit off the condenser area when you wash the car.
A musty smell is a separate issue
Damp, musty air usually comes from moisture in the evaporator housing or a blocked drain, not from low refrigerant. Running the fan a minute after shutting off the A/C helps dry it. If the smell persists, have the drain and filter checked.