You should keep your “green card” valid at all times and plan to apply for naturalization while it is valid.
As a U.S. permanent resident, you are expected to carry a valid green card with you. The naturalization process is taking several months and sometimes up to a year. Not having a valid “green card” can lead to difficulties in obtaining employment, a driver’s license, traveling abroad and much more.
USCIS used to issue an I-551 stamp for those with a pending N-400, Naturalization Application, who had an expired LPR or “green card”.
This I-551 stamp served as evidence of the person’s valid permanent resident status. However, a new USCIS policy says that ”a pending N-400 does not exclude an applicant from filing an I-90 and he/she must keep his/her “green card” current up until the naturalization process is completed.”
In general “green cards” are issued for ten years. Before the ten years are up, the green card holder is expected to renew the card by filing Form I-90 with USCIS.
It saves you money and time if you don’t want to renew your “green card” to start the naturalization process at least two years prior to your “green card” expiration.
If you are concerned about this process, you should consult with an attorney.