For example, apps such as Keynote and garageband I don't use, and I don't want to update them to waste space, will it make my system run slower? Will there be any negative effect?
MacBook Pro (Retina, 13-inch,Early 2015), OS X El Capitan (10.11.5)
FWIW, updating an App won't change the space taken by very much if any. For the most part nothing will change if you don't update an app that you don't use. If you decide to use it in the future of course updating it would be a good idea.
As long as you do not start the app, nothing happens.
but if you start it, for example by clicking a file with an extension that starts such app....
What happens if you click a .pps file (presentation)? it will probably start keynote...
I suggest to update the apps from AppStore when there is an update; the size will not change significantly, when it does not run, it is not taking resources.
It is not wise to uninstall Apple standard apps because there are common resource files: some may use files that are used by another apple app too...
So my macbook won't slow down i.e. become slower if I don't update the apps?
What happens if I don't update apps that I don't use?
