Houston is more senoir and everything will take longer. By the time you get a line in IAH on the 756 as an FO, you can hold 737 CA in EWR. Reserve times are much shorter in EWR than IAH. I've heard some say they were on reserve 1/2 month. I was on reserve EWR 737 FO for a couple of months. I never was on reserve in the 756.