So you should be able to get another reentry permit valid for another 2 years and then a third reentry permit valid for 1 more year. After that, it gets toughe

So you should be able to get another reentry permit valid for another 2 years and then a third reentry permit valid for 1 more year. After that, it gets tougher and USCIS will look at various factors to gauge whether a green card holder has given up his or her green card, including time in the U.S., home in the U.S., assets in the U.S., employment in the U.S., family in the U.S., etc. But at a minimum, without a reentry permit, you should never be outside the U.S. continuously for more than 6 months.