My commute ranges from 39 steps to my shop, to 8km (one way) to the co-op, to a 50 km cycle commute to the frame shop.
If I am in the city I can just throw my bike on a bus (although this has never happened) and if I am in the country can call my partner if I have a road emergency and he will drive out to meet me although this has never been needed.
I have so very few mechanical failures... might have something to do with being a bike mechanic... last failure was component related and I had to walk 3 km back to the co-op and fabricate a replacement part.
If my A bike was unavailable, which would be the bike I planned to use, I could use my b, c, d, e, f , g, h, i, j, k, l, or m bikes instead.