A Green Card holder must Renew a Green Card every ten years to maintain his/her status as a legal permanent resident of the United States. The card holder has to pay a biometrics fee of $85 to the USCIS for the green card to be renewed. This fee is subject to modification if the USCIS wishes to increase them in due course.
A Green card may be renewed even after it has been expired, but it is safe to renew it before the expiration date. If the date of renewal and the date of expiry have a big gap, the USCIS may consider it as a misdemeanor. A Green card is considered as a legal document which will help prove that the holders are not undocumented and still have a legal status in the United States of America.
It is sensible to apply for U.S. Citizenship rather than renewing the green card every ten years. It helps in saving the costs and time as well. The holder can apply for U.S. citizenship after five years from obtaining a green card, provided they meet the necessary requirements and file a Form N-400, an Application for Naturalization with the immigration agency. There is a onetime fee charged by the USCIS of $595 for filing and $85 for biometrics. Once the citizenship is given to the holder, it cannot be revoked by the country not do they have to renew it every ten years like they do for the green card. Like the green card, there is no expiration date for Citizenship. The holder only has to pay for it once and can be free of fear from those questioning their status as a U.S. Citizen.
Post Script: USCIS is set to increase fees for most of the immigration and naturalization applications. If the proposed fee increase comes to effect, the new citizenship application fees will be $640 instead of $595.