I'm not really sure what you mean by this? In my experience redesigns occur when new features are added, major updates, or changes to the team (whom chime that something should change). Yes likely everyone will redesign at some point, but to do so just for a test?

Based on this article, only larger changes should be done by smaller startups. But smaller startups have less resources to throw at larger changes. I mean, what of we're not planning on redesigning our web page?

You don't do things for tests. You do the tests because you want to change something.

That said, the kind of results startups could get by tests are usually obvious at the balance sheet (or some other big metric) anyway, without any kind of formalization. If you have one of the rare situations where it isn't, go ahead and do a formal test, but I wouldn't recommend anybody to lose some sleep over it.

The point of the article is to help small startups understand that a/b testing is not off the table. Of course startups will have to decide where the highest ROI is themselves. Given a point in time, the highest ROI may not be a/b testing.