> What's the cost? The cost is exactly what is pointed in the original tweet: > a requirement to keep two separate things aligned through future changes is an

> What's the cost? The cost is exactly what is pointed in the original tweet: > a requirement to keep two separate things aligned through future changes is an “invisible constraint” that is quite likely to cause problems eventually Code changes, and if those two identical or similar pieces of code are likely to change together, now whenever you change one you have the cognitive load to also change the other, or risk having them go out of sync. Of course, when the two pieces of similar code aren't likely to be changed together, they should be kept separated