Keep an eye on the outside unit as time goes by. The coil face outside (fins behind the metal grate all around the unit) will get dirty with dust and leaves with time. Just wash the coil face out with a hose. All the debris will fall to the bottom and wash out.
Once you are ready to shut the A/C down for the year (usually in fall). Turn the A/C breaker off.
Wash it out in the spring and turn the breaker back on.
And wait for summer to arrive!
Note: running the AC on cold days may do damage to the system.
Emerald Sheet Metal Ltd.HVAC Contractor