Dear leaner,

Every thing has a expiry date like as the certificates too ,so for SEBC which is of 3 years validity period earlier.

Obc certificate certainly has to be renewed for each and every year.

Where as for domicile ,infact it is valid for lifetime,if you have permanant address ,in case of temporary then the validity is 2 years ,since many of the institution recommend 6 months old domicile certificate.

All the best.