Packages cache
I clear the package cache every now and then.
To see some statistics about packages and cache:
yay -Ps
Then to clear cache:
yay -Sc
Logs
To see disk usage:
journalctl --disk-usage
Archived and active journals take up 667.8M in the file system.
And to delete part of logs (for example):
journalctl --vacuum-size=200M
Home directory
Also I use qdirstat to see statistics and clean my home directory → GitHub - shundhammer/qdirstat: QDirStat - Qt-based directory statistics (KDirStat without any KDE - from the original KDirStat author)