If you're going off the gauges instead of just dumping in the required amount of refrigerant for the system as designed, you might have to top it up in full summer as the ambient temperature may not allow you to charge the system without getting it overcharged. It's tricky aiming for the right pressure at lower temperatures, easy to under/overshoot.

Also, if the system has been at ambient pressure for long, replace the reciever/dryer as it might be saturated. And replace the test port schraders, they're very often the source of leaks in AC systems.