If your product is simple enough to not need a tour, you should design it like that; MOST products are definitely simple enough to not need a tour. But if you'

If your product is simple enough to not need a tour, you should design it like that; MOST products are definitely simple enough to not need a tour. But if you're making Photoshop, or a deep-functionality video editor, or an enterprise accounting application, or a diagnostics utility or... If you're building any of those things (or something complex like that), don't be afraid to keep it complex and use a tool for building user familiarity. That's good design, actually. No 'one-size-fits-all' solutions on UX, I'm afraid.