It’s a recurrent topic. The administration is generally not prepared for globe-trotters. You just cannot not live anywhere, a physical address continues to be a must. In Switzerland if you officially leave the country, on your return you must show that you have paid taxes somewhere else. So we are again in this limbo. We will not profit from the country but we should still pay health insurance and taxes, if we plan to come back to Switzerland at one point in the future (see Loi federale sur l’impôt federale direct and FAQ about health insurance in Switzerland).
Still looking for having one administration who accepts the globe-trotters. In Switzerland the Old-age, survival and invalidity insurance (AVS) already mentions globe-trotters. It is a beginning!
So in our case, we will keep paying expensive health-insurance and taxes in Geneva, where we sub-let our apartment but where we do not live in-facto. I could choose to leave officially the country and give my address in Portugal, but I just do not want to go through the bureaucracy in Portugal neither lose more of rights in Switzerland.