I'm currently running three days per week, and I usually run the same distance for each day of running during the week. However, that will change in the future. When I get the three days up to 5 miles, I'll cap my Monday run with the 5 miles. That will be my rest run. I'll continue to increase the Wednesday and Saturday runs until they reach 7 miles. I will cap the Wednesday run at that value for my medium run. I'll increase the Saturday run to 10 miles, and that will be my long run.
I should reach the 5 miles by the end of the year, the 7 miles by Spring, and the 10 miles by Summer. However, my body will determine what actually happens :)