Certain parts of my route are usually the same but I try a lot of different roads to add variety and relieve boredom. Safety is always paramount and I never ride on certain roads that are too busy, narrow, etc. However, I can take a lot of different roads to work and back with close to the same mileage. When we are on daylight savings time, I sometimes ride a much longer route along local greenways that doubles my afternoon commute distance. I love going that way because there is no traffic along most of the route and it's very scenic, but it doesn't seem safe riding that far in the dark this time of year -- plus the greenway officially "closes" at dark. I probably would vary my route more often in the afternoons except my wife is always ready to eat dinner when I get home and doesn't appreciate it when I am late. I tend to take longer routes home when she has book club meetings or isn't home for some other reason. I don't often add much distance to my morning commute because I'm trying to get to work on time.