Why YSK: Because you deserve to have peace of mind. Your privacy can mean your safety. I found out about this today, and in this comment I mentioned it and said I would make something more detailed.
I bet you heard that Google tracks you, as have I. But it's insanely daunting to see every movement, app and thing you have interacted with on your device for the last 8 years just laid out in front of you neatly. When you add your google account on your phone(or any device), it tracks this, with a timestamp, including:
-any app you used(including Contacts, Calendar, Phone, and when you pressed your home screen button-it is regarded as Samsung UI Home etc.)
-apps you viewed on google play
-map area on maps(you don't even have to search a specific place in order for it to get logged)
-if you called a place from maps(if you press the call button from maps to call a place and make a reservation, for example)
-images you saw and searched for on your browser
-location, video and voice notes and more
It is mentioned that if you log in on another device, it can keep track of this on that device as well.
#What can you do?
The first thing you can do is turn it off. Log on your google account, press the icon on the top right, then press on "Manage your Google Account". On the left side you will see a panel, choose "Data and privacy", and scroll on the center of the screen to see History settings, and press on My activity. You can choose to turn it off if you want. Make sure to stroll around to manage your advertisement settings, location settings, subscriptions and so on.
I also recommend switch to Proton Mail if you can.
#How I found out?
Recently, as you probably know, Youtube decided to be foolish(yes, more than usual) and force its users to either consume ads or buy Premium, blocking you after three viewed videos if you use any form of ad block. I said ew, no. Let's use yt clients that don't scrape your data and allow you to have privacy and no ads, it's about time I jump ship.
I didn't want to have to manage every subscription and videos in playlists manually(it would take days). I wanted something for my desktop, and I stumbled upon FreeTube. They have a guide that tells you how to export subscriptions and videos, the whole thing.
Following the instructions, I inevitably stumbled upon my managed data. It's a weird feeling seeing all that was. I vaguely remember how I felt in those years, but I never thought I would see what I was doing or what app I was using then. Inevitably we forget some trivial things in our lives, but this is what gets to be remembered, and this is the proof that we existed. It's strange.
Ending note: I assume most people here probably already know this, but I just wanted to pass this along for awareness purposes. I knew that I wanted to have random stats at the end of my life to like, review and read, but not like this.
Wait until he finds out about Google Maps Timeline.