Warning: I learned the hard way that a 'crumb coat' is not just for fancy cakes.
I was at a big family picnic in Portland last summer, bringing a simple two-layer chocolate cake. It was hot, maybe 90 degrees, and I skipped the crumb coat because I thought it was just for smooth, perfect frosting on wedding cakes. I just slapped the final buttercream on. By the time we cut it, the whole thing was a mess of dark crumbs floating in white frosting. It looked gray and dirty. My cousin said it looked like a storm cloud. That one fail changed my whole view. Now I do a thin crumb coat on every single cake, even a basic birthday one, and chill it for 20 minutes before the final layer. It takes a bit longer, but the cake always looks clean. Does anyone else have a simple step they used to skip but now swear by?