Can someone give me an example where the idiom 'The end justifies the means' is acceptable?

Maybe you have to go around doing something in a way most people wouldn't. More than likely you did something risky in a solution some people would consider off or a waste of time. When I bought my house the previous owner painted over natural oak in several places of the house. I decided to strip it in some areas and not others, stripping is time consuming. So everyone says, it takes forever just buy new, which is what most people do. But I stripped it and the end result was worth it. But basically, it is there to make sure that before you decide you want to do something make sure the outcome will be with your risk or time.