Your Mac includes daily, weekly and monthly scripts to serve this purpose, so macOS scans your computer and removes some old caches, log files and the like, but sometimes this just isn’t enough. This is where third party Mac cleanup programs come in handy, but you can do it just as well yourself if you have enough knowledge about how macOS works, what kind of low-level commands you need to run in Terminal and which files you can safely remove from the system library without harming the performance of your Mac.