To keep a cars battery charged you should start the car up and drive it for 10 to 20 miles at least once per week.
A car can go longer than week without being started but the longer it sits the more chance it has of the battery going dead.
It's good to start the engine and get it warmed up so that moisture burns out of the oil.
If no oil goes through an engine for longer than a year or so then the engine can sometimes seize up.
You also need to drive your car around at least once per month or sooner to keep the tires from getting flat spots or becoming out of round.
The worst thing for tires is for them to sit around in one spot.
So you need to drive it even around the block to help keep the tires from getting flat spots.