Letting your car sit for too long is not very good for the car and could cause problems with the tires getting flat spots and causing the batteries to go bad.
You don't have to drive your car every single day but you should drive it at least once or twice per week to keep the battery charged and to keep the tires from developing flat spots and going bad.
Tires are meant to be rolling down the road and when they sit too long they start to go bad so by letting your car sit longer than a month you risk the tires getting flat spots which can then lead to a blowout of the tire on the road.
I have a few vehicles and sometimes I let my truck sit for a few weeks when I only need the car to drive but I still drive the truck at least twice per month even if it's just to drive around town for awhile.
Driving even just around town or down to the post office etc helps to keep the battery up, keeps the engine from sitting too long and keeps the tires in good shape.
The same goes for my travel trailer or other trailers I have that sit sometimes.
If I let the travel trailer and other trailers sit too long the tires go bad quicker so I will sometimes just hitch up the travel trailer or other trailer to my truck and take it for a drive down the road even when I have no other destination to go too.
Also if your car sits too long as in longer than a month without driving it the gasoline in the tank will go bad and you'll need to drain the old gas out and put fresh gasoline in.