Hello,

Domicile or residential certificate has a life long validity. You don't need a new domicile certificate unless you are migrating permanently to some other place. But still in a some states domicile certificate comes with a maximum validity period but, it's about a few states and depends upon state to state. But domicile or residential certificate comes with a minimum validity of six months. You can apply for Domicile certificate via online from your state government's concerned website or you can apply offline by visiting to your Block office, Tehsildar office etc.

Good Luck.