The sweet spot would be to not have an all or nothing proposition, but to be able to work with fluidity in the beginning, and then to harden the result later on

The sweet spot would be to not have an all or nothing proposition, but to be able to work with fluidity in the beginning, and then to harden the result later on by adding in various layers of sanity checks, of which typing could be one. It's unsurprising that Airbnb—after having succeeded—find that they could have eliminated some of their current problems by making a trade-off earlier on. A parable: a baker has a shelf of many different flours that she uses to make different kinds of bread. Being the only person in her small bakery, she relies purely on muscle memory and habit to know which flour goes where. She experiments a lot with different mixtures and kinds bread. Later, some breads have turned out to be more popular than others, and she's doing well. She hires a couple more bakers, and now finds that she needs to label the flours, write down recipes for the successful breads, and has to establish procedures and guidelines for restocking. Different people have different habits, and muscle memory transfers poorly from person to person. When she was starting out, she benefited from short feedback loops. The shorter, the better. Later on, the benefits of short feedback loops wouldn't be any diminished, but the need for reproducibility has become much larger than it was at first.