Structuring a Rust mono repo

Hello!

I am trying to setup a Rust monorepo which will house multiple of our services/workers/CLIs. Cargo workspace makes this very easy to work with ❤️..

Few things I wanted to hear experience from others was on:

1. What high level structure has worked well for you? - I was thinking a apps/ and libs/ folder which will contain crates inside. libs would be shared code and apps would have each service as independent crate.
2. How do you organise the shared code? Since there maybe very small functions/types re-used across the codebase, multiple crates seems overkill. Perhaps a single shared crate with clear separation using modules? use shared::telemetry::serve_prom_metrics (just an example)
3. How do you handle builds? Do you build all crates on every commit or someway to isolate builds based on changes?

Love to hear any other suggestions as well !