How long should school years be?

Should school years stay the same or should they be year long? I think that schools should be year long. I think this because over the summer kids loose so much of what they learn the past year over summer. If we had year round school there would be breaks but none of them would be long enough that you would forget what you learned.
Another thing is that most kids think that having year round school would take away there vacation time but really ,in my opinion, we would have better breaks. If we have year round school we would have breaks more often. Most schools go with the 45-15 plan. This is where for every 45 day you are in school you get 15 days off. You would also still have built in breaks for the holiday. I would much rather have breaks more often then on long break in the summer.