pip, conda, npm, .gradle, .cargo caches — are they safe to clear?

Short answer: yes. Every package manager keeps a download cache so it doesn't refetch the same package twice. They're pure caches — clearing one just means the next install re-downloads what it needs. On a dev machine they routinely add up to 5–20 GB.

Where each cache lives (Windows) and how to clear it

pip

Cache: %LOCALAPPDATA%\pip\Cache — often several GB thanks to large CUDA/torch wheels.

pip cache info      # see the size
pip cache purge     # clear it

conda

Cache: C:\Users\you\.conda\pkgs (or your Anaconda pkgs dir).

conda clean --all

npm / yarn / pnpm

npm: %LOCALAPPDATA%\npm-cache. yarn: %LOCALAPPDATA%\Yarn\Cache. pnpm keeps a global store.

npm cache clean --force
yarn cache clean
pnpm store prune

Gradle

Cache: C:\Users\you\.gradle\caches — one of the biggest offenders for Android/JVM devs.

# safe to delete; Gradle rebuilds it on next build
Remove-Item "$env:USERPROFILE\.gradle\caches" -Recurse -Force

Cargo (Rust)

Registry + git caches: C:\Users\you\.cargo\registry and .cargo\git.

cargo cache -a        # needs: cargo install cargo-cache
# or delete .cargo\registry\cache manually

NuGet (.NET)

dotnet nuget locals all --clear

When not to bother

If you build the same projects daily, a warm cache speeds you up — clearing it just to reclaim a couple of GB you'll refill tomorrow isn't worth it. Target the caches from tools and languages you no longer use: the Gradle cache from that one Android experiment, conda envs from a finished course, the Rust registry from a project you shipped a year ago.