I've seen a lot of people relearn the same couple of lessons over an over again. One, most of the things you believe scale linearly scale at nlogn because of p

I've seen a lot of people relearn the same couple of lessons over an over again. One, most of the things you believe scale linearly scale at nlogn because of physics. Storage is much worse, scaling at n^1.5. What fit in a single 4U case is orders of magnitude slower when it no longer fits in a single data center. Inserting records into a table with a billion rows is much slower than a table with ten thousand. Wipe the surprised Pikachu look off of your face. Second, every architectural choice needs to be reviewed every time traffic increases by an order of magnitude, and preferably before so that you have time to stew on possible solutions and allow serendipity the time it needs to find you a better answer. If you have made too many architectural decisions, you will find there aren't enough hours in a month to keep up, even if you never sleep. That's the real reason we practice Principle of Least Power. Not security, but job security. Keep the system small enough that you have time to keep the plates spinning while also implementing new features to attract or retain customers.