I've grown my beard out before, to about 2.5 inches if I had to guess. Right now I keep my beard trimmed to about 7mm.
I wouldn't grow both out though, then I'll just look like Jesus.
I think the answer is to grow my pubes out. Like super long, I'm talking 3 or 4 feet. Then I can enter some pube crafting competitions and make a lot of money. Okay guys, it's been decided. Thanks for all of your help!