Kind of a broad question. I wonder why people take notes - Is it for studies or learning? Is it just to remember things? Is it to make your own map of your knowledge? Is it because you just want a place to vent out your feelings into the void?
What do you use to accomplish that? App? Paper? A chat room?
I used to have two separate note systems, a journal and linear academic notes. Journal was always free-form and digital; academic notes started on paper using the Cornell method and moved to digital a couple of years ago.
Very recently I’ve moved to a digital Zettelkasten via Obsidian.md and I’ve basically combined the two, previously separate, systems.
Journal type entries are still kept generally segregated from my Zettels, but cross-linking can now happen.
My specific speed at digital note-taking has always been good, but what was lacking before was the a ability to backlink, which is a substantial strength in Obsidian.
Imagine your own personal Wikipedia for the bits of knowledge relevant only to you. That’s Obsidian. If you need a framework, that’s Zettelkasten.
But to answer your additional questions, I take notes to reference and retain. I’ve never been able to trust my complete memory recall, but I can usually recall a cue or keyword. With notes, especially digital notes, a cue or keyword search will get me right to what was on the edge of my mind. This has been especially helpful as I work on my undergrad, and as I move into the portion of my undergrad requiring more research, I anticipate large dividends from my Zettelkasten.