大きくやると失敗するのはウォーターフォールで経験済み小さい投資をたくさんする
進捗に影響を与えない程度の変更を行うのがよい
「So, what is the right amount of investment? A huge up-front investment, such as trying to design the entire system, won’t be effective. This is the waterfall method, and we know it doesn’t work. The ideal design tends to emerge in bits and pieces, as you get experience with the system. Thus, the best approach is to make lots of small investments on a continual basis. I suggest spending about 10–20% of your total development time on investments. This amount is small enough that it won’t impact your schedules significantly, but large enough to produce significant benefits over time. Your initial projects will thus take 10–20% longer than they would in a purely tactical approach. That extra time will result in a better software design, and you will start experiencing the benefits within a few months. It won’t be long before you’re developing at least 10–20% faster than you would if you had programmed tactically. At this point your investments become free: the benefits from your past investments will save enough time to cover the cost of future investments.」
—『A Philosophy of Software Design, 2nd Edition』John K. Ousterhout著
https://a.co/iKKoOs0
ユースケースの導入の時に失敗したので分かる
大規模な投資は厳しいものがあることは実感としても感じる
