I've yet to find a different route that is shorter or quicker so the same it is.

For Weather, Mostly
 

I have two different paths between work and home. Both are equally hilly, but they differ in how exposed they are to the prevailing winds. One has more road (vs paved sidewalk/path) exposure and has slightly risker bits, but is a bit longer. I select the route based on the weather, mostly, and decide while en route.

almost always the same 5 mile route for me. it's the one that has the best balance between safety and quickness. there are occasional divergences for specific errands.

i would love to have the free-time to stretch my 5 mile afternoon commute into a 20 mile scenic route, but i've got little ones to tend to these days. free-time is no more.