Where do you hear that "common wisdom" from, though? Probably the same people that tout and follow the "12 startups in 12 months" mantra. I'd be wary of calling that common wisdom. If you think your idea is a good idea, and you think your business plan is solid, why would you think you're investing too much time in getting traction? All I'm saying is don't expect traction in 1 month. Instead, go in expecting that it'll take 12 months. If you don't have traction by then, or at least a solid direction from user feedback, then you should reevaluate. Ideally, you should be getting user feedback from day 1. And if you aren't, your idea or business plan sucks. (Or you need to grow as a marketer.)

Of course, this isn't a hard and fast rule. Sometimes an idea sucks, and you'll know that just by the fact that you can't get anybody interested in trying your product, even before asking to pay for it. That's where validation and testing come in, so I'm not saying to not validate and test. That's always step 1. All I'm saying is that new founders give up on good ideas way too early. Their expectations of overnight success do not match reality. Validate and test and iterate can take a long time.

And it's worth noting: sometimes iterate is not iterating on your product, but iterating on yourself as a founder. I stood in my own way a lot as a new founder, focusing on the wrong things. It took awhile to get past that. After I did, growth was much easier. But if I gave up early, assuming my product sucked, I would have never gotten to that point.