To save on shaving expenses and pain (sorry, Gillette)
To study the growth of microbes, bacteria in a bearded environment, right under your nose
To look like your bearded hero (who they are eludes me for the moment)
To differentiate youself (a beardo) from a weirdo
To keep the total hair (neck upwards) constant, particularly as you advance in age -heck, I must be in this category now, just had a birthday too.
So what do I do? To grow or not to grow, THAT is the question.