Mostly the only time I grow my beard out is when I have a fever blister. That's because the best treatment for that particular malady is just to leave it alone. (All the creams and lotions they sell for it are just growing cultures.) So rather than leave a small patch on the upper lip unshaved I just stop shaving everything above the neck.
The thing is, I don't really like having facial hair. It's itchy and distracting. I'm sure you get used to it. And maybe I'll give it another try one of these days, after the beard I briefly had in college. But at present it's one of those things I look forward to getting rid of, which I'll be able to do tomorrow.