What Impact Does the Length of the Marriage Have?

Yes.

If the couple is married for less than two years at the time of the interview and the case is approved, only Conditional Permanent Residence will be granted – not full unrestricted permanent residence. The non-citizen spouse of a couple married for less than two years at the time of interview would receive a Conditional green card valid for only two years from the date that the green card is approved, as opposed to an unconditional card valid for ten years from date of approval for someone married more than two years at the time the case is approved. Without action by the Conditional Permanent Resident to extend their status by filing an I-751 Petition to Remove Conditions near the end of the two years, not only the card but the Conditional Permanent Resident status expires.

By contrast, with “unconditional” permanent residence, not only is the card valid for ten years but when it expires only the card itself expires (as evidence of status). The foreign national is still considered a “permanent resident” even after the card expires…just one who will have trouble returning from international travel or documenting employment authorization until they renew their card. In addition, a marriage already of long duration at the time of interview may – as you might guess – be viewed more favorably by USCIS in making a determination on the “bona fide” (real, good faith) nature of the marriage and so cause them to more readily approve the I-130 Petition for Alien Relative.