Anyone normal modern car should have no problem being idle for 1 month without starting. Some works fine even after 2 months. It depends on the car's battery health. And also if you have parasitic draw. If your car is still standard without mods like entertainment system or dashcam (connected to fuse) then it should be fine to start monthly. Or if you want to be safe, every fortnight will do.

In my personal opinion, it is better to leave the car idle as it will go into deepsleep after inactivity for long time. In this mode, battery consumption is very low. If you start it everyday, you will need to compensate back the battery because it suck a lot of power when you crank the car.