When you're registering on a centralized exchange, are you reading their Terms and Conditions?
I did not read all of their Terms and Conditions. Never because I will waste my time to read it. I only search for information I want to know. If they have FAQs, I will look at FAQs first before searching in Terms and Conditions.
What about their Privacy Policy?
It is not my consideration if I use a centralized exchange.
When your favorite centralized exchange sends you an e-mail about updated Terms and Conditions, do you take your time to read the update?
I surely will check their update in Terms and Conditions if I get their notifications in email or on their social media channels.
Not all platforms will keep you notified with their changes in Terms and Conditions.
When you're downloading software like Electrum or Trust Wallet, are you verifying the downloads before executing files or installing?
I did not verify wallet softwares in the past but I am learning to do this.
Did you ever thoroughly, properly plan a way of storing your seed safely and backups for it?
Make backups. Store backups offline. Avoid third-party storage services for your backups.
Do you store the majority of your balance on a safely created, properly stored Bitcoin wallet that only YOU own (a seed generated by you)?
I store my coins in different wallets and on some devices. I don't store all my coins in one wallet or on one device.