One extra point: Don't Add Caching Yet. 1. wait until something presents itself as a bottleneck 2. optimize it until it's not a bottleneck anymore 3. wait u

One extra point: Don't Add Caching Yet. 1. wait until something presents itself as a bottleneck 2. optimize it until it's not a bottleneck anymore 3. wait until it presents itself as a bottleneck again anyway. ...Then add caching. You'll never find the low-hanging yet dog-slow fruit if you put your aggressive caching scheme in place right off the bat. If you have a bunch of poorly optimized code running with a ton of caching to hide it from you and you suddenly have enough traffic to cause scaling pain, that's a big problem. Speed it up. Then cache it.