I never used to care much which seat I got on a plane. But now that I'm flying with my husband and children, I find it stressful that I can't usually get us sea

I never used to care much which seat I got on a plane. But now that I'm flying with my husband and children, I find it stressful that I can't usually get us seats together in advance. They've always accommodated us at the actual airport checkin so far, but it does add a big worry to the travel day. Solo travelers prefer to choose a seat in an empty row, but the plane is going to be full anyway. It's just an inefficient system.