It‘s more a result of the shortage of available rental flats so people can easily find a successor by themselves. Outgoing renters have negotiation power and th

It‘s more a result of the shortage of available rental flats so people can easily find a successor by themselves. Outgoing renters have negotiation power and the incoming ones have to adhere to whatever date they want, resulting in cascading effects. New flats in big cities have arbitrary (ie monthly) moving dates in the contracts nowadays to bring them in line with reality. But it is never a problem to agree on any random date between you and the next guy, as long as you provide somone willing to take it over per that date. I‘m Swiss and never moved on one of the official moving dates...