Every frontend project keeps three caches, and only one is node_modules

Everyone knows about node_modules. Fewer people notice that a modern frontend project keeps at least three more caches beside it, all of them derived, all of them per project, and none of them removed when you stop working on it.

What a project actually holds

Find them across every project

find ~ -maxdepth 6 -type d \( -name .next -o -name .turbo -o -name .vite \) \
  2>/dev/null -exec du -sh {} + | sort -h | tail -20

find ~ -maxdepth 7 -type d -path '*/node_modules/.cache' \
  2>/dev/null -exec du -sh {} + | sort -h | tail -10

A .next folder on a large site is routinely a gigabyte, and it exists in every project you have run a dev server in, including the tutorial you followed once.

Clearing them in bulk, safely

These are the safest folders on a developer Mac to remove, because every one of them is defined as derived output. The only cost is the next build, and for a project you are not working on there is no next build.

find ~ -maxdepth 6 -type d \( -name .next -o -name .turbo \) \
  -mtime +90 2>/dev/null -print0 | xargs -0 rm -rf

The -mtime +90 filter is what makes that command reasonable rather than reckless: it only touches folders untouched for three months, which excludes anything you are working on.

The remote cache question

If a monorepo uses a remote cache for its task runner, the local .turbo folder is a mirror rather than the only copy, which makes it even safer to remove. That is worth checking once, because it changes the calculation for the whole team.

Once the derived folders are gone, node_modules across every project is the larger number, and the package manager stores are the shared copy behind them.