The following table provides general guidance for cert expiration. The columns headed with "XMPT (Months)" indicate the default periods applied by the system, but all of those can be overridden by the seller when they approve the individual certificate.

State	Exemption Certificate Expiration	XMPT (Months)	Resale Certificate Expiration	XMPT (Months)
Alabama	Renew annually	12	Valid for period set (max 48 months)	48
Alaska	Valid until end of calendar year	12	Valid until end of calendar year	12
Arizona	Valid for period set (max 48 months)	36	Valid for period set (max 48 months)	48
Arkansas	No stated expiration period	36	No stated expiration period	48
California	Valid until revoked in writing	36	Valid until revoked in writing	48
Colorado	Valid until cancelled by Department	36	Valid until cancelled by Department	48
Connecticut	3 years	36	3 years	36
D.C.	Expiration stated on Certificate	24	Valid for one year	12
Florida	5 years	60	1 year	up to 12 - ending on 12/31
Georgia	Valid until revoked in writing	48	Valid until revoked in writing	48
Hawaii	Does not expire	48	Until revoked in writing	48
Idaho	No stated expiration period	48	No stated expiration period	48
Illinois	Varies depending on purchaser	48	Valid indefinitely (update every 3 years)	36
Indiana	Does not expire	48	Does not expire	48
Iowa	3 years	36	3 years	36
Kansas	Valid for recurring purchases	48	Valid for recurring purchases (max 12 months)	12
Kentucky	4 years	48	Valid until change in operation	48
Louisiana	Generally valid indefinitely	48	Valid for period indicated on certificate	48
Maine	No stated expiration period	48	Valid for five years	48
Maryland	5 years	60	Valid until revoked	48
Massachusetts	No stated expiration period	48	No stated expiration period	48
Michigan	4 years	48	4 years	48
Minnesota	Does not expire (update every 3-5 years)	36	Does not expire (update every 3-5 years)	36
Mississippi	State does not issue certificates	36	State does not issue certificates	36
Missouri	5 years	60	5 years	60
Nebraska	Valid indefinitely	48	Valid indefinitely	48
Nevada	5 years	60	Valid until revoked in writing	48
New Jersey	No stated expiration period	48	No stated expiration period	48
New Mexico	No stated expiration period	48	No stated expiration period	48
New York	No stated expiration period	48	No stated expiration period	48
North Carolina	Valid for recurring purchases	48	Valid for recurring purchases	48
North Dakota	No stated expiration period	48	2 years	24
Ohio	No stated expiration period	48	No stated expiration period	48
Oklahoma	Valid for recurring purchases	48	Valid for recurring purchases	48
Pennsylvania	No stated expiration period	48	No stated expiration period	48
Rhode Island	Valid for recurring purchases	48	No stated expiration period	48
South Carolina	No stated expiration period	48	Valid until cancelled or revoked	48
South Dakota	Valid until cancelled by purchaser	48	No stated expiration period	48
Tennessee	Valid for recurring purchases	48	Valid until revoked in writing	48
Texas	No stated expiration period	48	No stated expiration period	48
Utah	Valid for recurring purchases	48	Valid for recurring purchases	48
Vermont	Valid indefinitely for blanket certificate	48	Valid indefinitely for blanket certificate	48
Virginia	Valid until notice from Department	48	Valid until notice from Department	48
Washington	Valid for recurring purchases	48	48 months (24 months for some businesses)	24
West Virginia	Valid for recurring purchases	48	Valid for recurring purchases	48
Wisconsin	Valid indefinitely (review periodically)	48	Valid indefinitely (review periodically)	48
Wyoming	No stated expiration period	48	No stated expiration period	48