One Word to summarize this section: "Efficiency"
The word "efficiency" succinctly encompasses all of Chapter 9's section on the usability testing in Steve Krug's Don't Make Me Think
It doesn't have to be expensive and time consuming
As I continue to build and develop my own design system and prototype, my familiarity with the website I am making quickly becomes my downfall, as I don't have a true perspective of what it is like to visit our page and try to navigate around. That's where usability testing -- having participants test and examine your page -- comes in. While in the past, people would spend thousands of dollars on big fancy usability tests, carefully curating the proper sample group and generating a giant scientific report, Steve Krug argues in this section that you don't need all that, and that you just need to be efficient. "Do-it-yourself" usability testing is the pinnacle of testing efficiency. You take three people, watch them closely as they work with your page, and then debrief over lunch. There is no muss, no fuss, and you have the time and resources to do it much more often, getting the essential feedback you need at every stage of the design process. Sometimes less is more, and there doesn't have to be some big corporatized solution to perform well.
Credit
Norman, D. A. (2013). The design of everyday things. MIT Press. Krug, Steve. Don't Make Me Think, Revisited : a Common Sense Approach to Web Usability. [Berkeley, Calif.] :New Riders, 2014.