Your permanent resident status does not end when the card expires. But you need a valid card to prove it for work, travel and many forms. Most green cards are valid for 10 years.
Your 10-year card expires within 6 months, or has already expired.
The card was lost, stolen or damaged.
Your name or other details legally changed, for example after marriage.
You received a card but it never arrived in the mail.
A conditional green card (valid for 2 years) is not renewed with I-90. File Form I-751 (marriage) or I-829 (investors) in the 90 days before it expires. See Conditional green card: removing conditions.
Create a USCIS online account at uscis.gov and choose Form I-90. Online costs less. Paper also works.
Pick the right reason on the form: expiring, lost, stolen, name change and so on.
Add papers: a copy of the old card (front and back) if you have it. For a name change, add the marriage certificate or court order. For a lost or stolen card, a short statement of what happened.
Pay the fee. The current USCIS fee schedule lists $415 online and $465 on paper. Check uscis.gov/g-1055 first.
Keep the receipt notice (Form I-797C).
Biometrics: USCIS sends a letter with an appointment for fingerprints, a photo and a signature at an Application Support Center. Bring the letter, your old card and a passport or other photo ID. Sometimes USCIS reuses earlier fingerprints.
Track the case online with the receipt number.
The receipt notice extends your card
For renewals, the I-90 receipt notice now extends your expired card for 36 months from the date printed on the card. It used to be 24 months. Carry the original notice with the old card. Together they prove your status, and employers can accept them for work.
Travel while I-90 is pending
USCIS recommends getting the new card before you travel if your card is about to expire.
If you must travel, carry your passport, the expired card and the original receipt notice. Airlines may not accept a copy.
If you have no card at all and need proof urgently, call the USCIS Contact Center and ask for a field office appointment for a temporary stamp in your passport.
If the card is lost while you are abroad, you usually need a carrier document (Form I-131A) from abroad, not I-90.
Waiting until the card is long expired.
Leaving the US with a lost card and no plan.
Filing I-90 for a 2-year conditional card.
Moving without updating your address with USCIS. Mail goes to the old place.