How long can a car stand unharmed, unused?

The starting point is that I will have to study from autumn onwards and reduce my expenses. I am a passionate motorcyclist and do not want to do without it. In Austria we have the possibility to deposit a license plate, also for cars. That’s why I thought I would only register my car in winter, and in summer it is parked in the garage. The question is, how harmful is this for the car? It would almost be 7-8 months and only 4-5 would be driven. safety and so save 200-300€ per year. My motorcycle survives the winter break quite well and I actually do nothing but leave the tank almost empty and 2-3x in winter the moped in the garage a little back and forth. But between 4 months and 8 is a big difference. So what do you say, this plan has future, or which drive forms are best suited for it (except for electric car there too expensive), and what measures should be taken to make a car such a service life I didn’t think I could ride a motorcycle all year round, only on a snow track I don’t think I could ride 2 wheels and in Hagenberg (Mühlviertel) I’m not sure how fast it will be cleared.