Interesting. Thanks for the tips. I've been using CleanMyMac for awhile to uninstall things etc... Is it safe to use in this minimal way?
There is no right or wrong answer to that question. It is true that CleanMyMac can help with removing obsolete files that are left by applications you’ve deleted, such as preferences. Typically, these are left in place in case you want to reinstall the app in the future. However, some apps can leave quite substantial files and it may add up over time. There are also plenty of people who argue that the system doesn’t need to support all these languages, especially if you only ever use one system language. Linux systems handle this much better and only install the languages you actually use.
There is generally no harm in letting CleanMyMac point you in the right direction in that case. However, the problem with CleanMyMac and comparable apps is at least threefold: (1) they encourage inexperienced users to take potentially destructive or at least harmful actions with little to no benefit, (2) they conceal their actions behind fancy user interfaces and (3) they may pose at worst security risks when developed sloppily or with malice, especially when they are overly interested in root access.
GGJstudios also suggested Onyx, but I can’t unconditionally recommend that app either. It should not be used lightly and there isn’t even a need to use it regularly. I also read that still Onyx uses custom prompts for gaining root access, which should at least raise some suspicion as to the professionalism associated with the development.
Bottom line:
(1) The system has a maintenance schedule of its own that should be left alone. It will deal with logs, caches files and other things.
(2) There is no need to delete every tiny bit of data after removing an application, but if you want to, I suggest using a tool from the App Store that is approved by Apple (these generally have no root access). I personally use TrashMe, which gives me a detailed list of files it suggests to delete, which I review with care.
(3) Removing unnecessary language files should be considered carefully. If you want this, I recommend the tool
Monolingual.