Do I really need residence somewhere? What if I live 3 months in each country? Notice also that I left my home country 15 years ago, and have been a legal resi

Do I really need residence somewhere? What if I live 3 months in each country? Notice also that I left my home country 15 years ago, and have been a legal resident of 3 other countries during that time. I wonder if I just forget about residency altogether. I can't find a clear answer for that.