I often install software to test and forget to uninstall them, which is a problem, since my space on disk is not that big.

Let me see how many packages I have manually installed (not counting their dependencies):

That's a lot!
I do not keep track of which ones I need to reinstall in a future new system installation.
But now that's something I need to do: keep track of which programs I need to have installed.

In my server, however, I have only vim installed (OpenBSD has a lot of services out of the box).
I'll probably install dovecot and git when I set up my mail server and git server.

I think I'm not alone. Most people install packages carelessly in their desktop while keeps just the necessary on their server.