It’s spring, and a homeowner’s thoughts turn to home improvement projects. If you’ve got a big one coming up, you’ll be thinking of hiring a contractor. Few relationships can be so fraught with conflict or misunderstanding – or even liens and lawsuits. But homeowners who’ve had successful relationships with contractors say if you take time on the front end, you can avoid a lot of the problems down the road. “When I would tell people, ‘I think we’re going to remodel,’ I heard nothing but war stories, horror stories,” said Emily Sue Pike, a retired high school teacher who had the main floor of her North Side home remodeled last year. “I had a good friend who builds homes, and I asked him, ‘If you were remodeling your home, who would you ask?’ ”