Your wall had a crack that you'd planned to fix. Now it's gone. Is someone playing April Fools' Day tricks? Not really. Here's what might be going on. During winter, heating dries the air, which you probably notice causes dry, itchy skin. Reduced humidity dries out your home, too, causing various parts to shrink accordingly. Thus, during winter, cracks in walls and separations in trim and woodwork begin to show up. As things get drier and drier, hairline cracks suddenly become more noticeable. Thus, winter and early spring are a good time to find and patch these elusive cracks. With warmer weather coming, homes are opened up, and humidity levels rise. Your home starts absorbing more moisture and suddenly, as your house begins to re-expand, many of these small cracks start closing up -- making them extremely hard to find. So, if you had a crack that you planned to fix and now it's gone, it isn't someone playing April Fools' tricks. It's just simple science. And that's the On The House tip for today.