If you don't feel like you need to take notes, then I wouldn't worry about it. Once you leave school, there's not necessarily a need for it. For me they are generally just reminders, like you stated.
The majority of my notes are placed in Google Keep. I know that Lemmy hates Google, but it's really convenient for me...since they are online I can access them from any device. And the app version sometimes comes pre-installed on my devices anyway.
If I only need to remember one simple, time sensitive item...then yes I often use a reminder app to notify me like you do too.
But here are some scenarios where I take notes in my notes app:
- Grocery lists. I can't tell you how many times I've gone to the store for only like 1 or 2 items and completely forgot to buy what I came in for lol
- Requests at work. Often, a task that is requested of me will be done over a landline phone. So I pull out my cell phone and take a quick note of the task to help me remember and make sure it is done correctly
- Semi-ordered lists of multiple tasks I intend to do. For example, suppose I am expecting family to come over one weekend. I'll have various notes that help remind me what I need to do and when. Things like different types of cleaning tasks, getting snacks, etc.
In my home, I also have a handwritten notepad of passwords to my accounts written in a cryptic partially pictogram cypher lol. If someone manages to find and figure them out, have fun with those accounts lol.
At work, I also often write notes directly onto my workbench itself in pencil! My workbench is a contaminated space, so I don't necessarily have my phone out. I use my phone to take notes while talking on the nom-conatimated landline. But at my workbench itself I write directly onto my workspace lmao. It probably looks a bit unprofessional, but I don't think it stands out too much and is easy to erase when done! The first time someone showed me that you could easily do this, my mind was blown lol. At work, I write workbench notes all the time lmao.
Your last paragraph reads rather odd to me. Poly relationships exist but involve mutual consent. That's the reason why cheating in many cases is not at all ok. Because the other party doesn't consent to it and it's done in secrecy and deep violation of the person's trust. It's ok to have multiple partners or have sex with other people. You can too if you want to! But everyone involved has to agree with that kind of a setup for a relationship. Hiding it and hurting the other person is almost always immoral and wrong, even if it "feels good" to you. There are ways that all parties can consent to make your "feeling good" not hurting or taking advantage of others.