Is it safe to manually "clear cache" of apps on Android? Ever since I updated Device Care on my Samsung Galaxy A10s running Android Pie, I lost my "Clear Space" option that clears unnecessary data, including cache of all apps including system apps on my phone! 

Since, I'm not installing any third party apps, for this purpose, I decided to manually "clear cache" of any desired apps from Settings > Apps > App name and tapping Clear Cache. To my surprise, I found the Gallery app has about half a GB of cache, and I immediately cleared it.

I realize that apps cache stuff to improve performance, predict data to auto fill on text boxes, and various other stuff, to improve user experience. But that's taking up a lot of my Internal memory!

My question is : 


Is this a safe practice? 
Will this procedure damage the executable or normal functioning of my app? 
Or, whether all these are dependent on the App developer / manufacturer ? 
For default apps like Gallery or Chrome is this a safe practice?
Clearing cache of apps is one of the to-do things if your app is laggy, unresponsive or misbehaving.

It's absolutely safe, unlike clearing data of apps which makes you lose all the app data, accounts, settings etc. 

For 1,4 a definite yes. For 2, 3 it is no. Re: safety being app dependent, it is possible that the cache is used for storing data and in the process of clearing cache, one may lose data. This is not a recommended way of app development, also mentioned in developer documentation 
and more of an exception, owing to bad practices. 

Android framework shows a "Storage Low" notification when the free storage space reaches a minimum threshold. But even before that when free space is 1.5 times (as of Android 10) of the threshold, apps cache is cleared to free space as much as possible before warning the user. Since Android 8 apps are allotted filesystem quota to store cache files within given limits. Apps reaching or exceeding quotas are given priority when clearing caches.

For more, see 


What is the purpose of the cache?
Android App Cache Security


You don't want to install third party apps but I would recommend even making it a scheduled operation (in case you frequently need to) for which I find SD Maid an excellent option (even the free version would do and I am not promoting this app, I am only recommending based on personal experience).