My experience, with production-type hatchery hens, is they lay right through the first winter. So, I buy chicks in say spring 2013. Those hens start laying in late summer/fall 2013. They'll lay straight through until fall 2014 when they molt and usually don't lay again until spring 2015. This is what surprises folks......"but they laid last winter, why did they stop now?" is a common lament in the early winter months! Those hens then lay until fall of 2015--a few less eggs a week than last year--and again molt and quit for the winter. Repeat, with steadily decreasing production, each year.
Again, this is with hatchery birds, and all hens that are production types--by that I mean not ornamental birds, or slower maturing breeds like brahmas or cochins, but the birds usually called dual purpose or other layers.
Thank you donrae for giving me a more detailed look at things. This forum has been sp helpful to me before I get started. It's nice to know these things ahead of time versus getting surprised by them.