This is the literally the first thing you should check for on a new codebase, particularly because modern build tooling recognizes the need and makes it easy. W

This is the literally the first thing you should check for on a new codebase, particularly because modern build tooling recognizes the need and makes it easy. When you have a.js depending on b.js depending on c.js and on and on, the latency on each network request (just to get the 304) really adds up and can drastically affect perceived speed. Indeed, if most of your users are on speedy connections, the difference between a 500 byte 304 response and a 50 kb re-download is pretty much immaterial compared to the latency of making the request in the first place.