It also depends on how you run your business. If you run it as a business with an intent to make a profit, the presumption is immaterial. The problem comes up more when you're doing things you'd do anyway. Paint toy soldiers, run model trains, ride horses or try your luck on the golfing pro tour with never quite making the cut, would all be a bit problematical. Toilet unplugger, not so much a problem. In both cases they look at all the facts of the situation to see if you have a realistic plan to make a profit and are working appropriately towards that.
(By the way, my understanding is the presumption is 3 out of 5 years of profit--except for horses is 2 out of 7.)[IRS Code 183(d)]