Both state and federal law require election officials to wait two federal elections before cancelling the registration of voters where the election official has received initial information that the person may have moved. The waiting period is required because sometimes the initial information suggesting that someone has moved does not mean they have actually changed their voting residency. For example, mail may be returned as undeliverable by mistake and the voter actually lives at the address. Or, someone may have changed their address for one purpose (such as a temporary work assignment, school, or military service) but they actually wish to continue voting in Michigan.
In addition, some voters who live in foreign countries may not have a U.S. address and they use their last U.S. address for voting residency purposes. Therefore, it is possible that someone who used to live at your residence is still legally using that address as their voting residence in Michigan, even though the person is currently living in a foreign country.