Waited too long

When I made the plane reservations for New York in September, the web site indicated seat assignments were not available yet and to check back closer to flight day.  I decided to check 2 days ago.  The flight out had half the seats still unassigned and I reserved two good ones for us.  The return flight, however, was another story.  There were only 2 unassigned seats on that flight -- obviously, they were ours -- and they were the last row!  I guess it's a popular flight.  It won't be fun, but the flight is reasonably short and we'll be tired.  There is a lesson learned in this, I suppose, such as checking such details frequently.