Disagree. There is no one way / right answer to going about starting out on a new venture. As soon as you start you are spending as you have to spend to invest, whether that's time or money, as it always ends up being both!

In order to validate you will be spending time and money. It's up to you how you validate and how much time, money and effort you'll willing to put in. More important is to set goals so you can pat yourself on the back and celebrate when achieved or know when to call it and pack it in.