I think this is excellent advice for developers too. We often get caught up tinkering with code because we enjoy it, when we should really be looking for an off-the-shelf or non-technical solution. If you can validate your ideas with nothing but google forms and manual email, all the better.
Definitely. All too often, I'm into building what can be bought (often bought for $0). I'm a developer because building stuff is fun, but it isn't always the right choice for the business.
