When Tom Wallerstein started his firm, several mentors gave him the same advice: Don’t work for free. It’s easy to see the problem with working for free. Giving away what you’re trying to sell isn’t exactly in the business plan. Unfortunately, this sage advice can only really be learned the hard way, through experience. Even if your gut tells you that taking on that client is a bad idea, this can be surprisingly tempting to a new firm or solo practice….