> I think perhaps a lot of projects start out using nightly with the assumption that within 6-12 months those features they are using will be in stable. In my

> I think perhaps a lot of projects start out using nightly with the assumption that within 6-12 months those features they are using will be in stable. In my experience, that is rarely the case. People mostly use nightly features because they just need to get something done, and these features make that easier. The tooling around Rust is quite good (rustup, cargo, docker), so if you follow the language a bit, judge which nightly features you opt-into, pin nightly version in your build environment, etc. breakage only happens when you actually have time to fix it and the fixes are simple. So the bar for how much easier a nightly feature needs to make your problem to overcome its costs is quite low. The moment you are using one nightly feature, the cost of using more is even smaller.