Back in college, I kept a great log of my guitar rehearsal time. It kept me on my game, and was the metrics for a little friendly competition between other players. It wasn't necessarily required, but I knew my professors and instructors preferred that I keep track of what I was doing.
Jump ahead more years than I'd like to admit, and I'm still keeping a rehearsal log. Whether it's guitar, voice over, or practice with an ensemble, the only way to not only stay crisp at your craft, but to continuously improve AND be prepared for any job that comes up, is to do the drills. Add a little challenge every day with something you haven't tried before, and hit 'record' to test how you do. It's one of the biggest benefits to being a studio owner!
BUT...rehearsing isn't just for us audiophiles. Any business has its moments in need of preparation. Do you give presentations, regularly conduct meetings, or do direct or phone sales? These all require scripts and skills that can definitely benefit from rehearsing. If you want to practice in front of an audience that can give you constructive critique, check out your local Toastmasters, or have a little houseparty of your most trusted friends and family.
Here's a great quote, from Publilius Syrus (1st century B.C. Roman author): “Practice is the best of all instructors." I've had some great teachers and mentors, but without practice, none of their teachings would have changed my life. I take these words very seriously.
So get your calendars out, get to practicing, and watch your skills soar!