Originally Posted by BengalCat

Other than an injury or bike damage while riding your bike the worst experience in cycling is to "run out" of gears. I'm fit, old, and heavy with impaired calve function and about a year and a half ago I went from a 32t to a 40t on my Domane road bike. I now need a 40t on grades where four years ago I would use a 28t.

In practical terms, if you have hills in the area where you ride your road bike and you like to climb be very liberal when you choose what the gear is on the top of your cassette.