You know you're allowed (some might even say supposed) to have different keys for different machines. They're basically free to generate and take up to no space.

Yes, but I usually add my public key to the authorized_keys file and turn off password authentication once i do login with a password. On top of that, I have a sshpass one line command that takes care of this for me. It's much easier than trying to manually type a password for the next time. I save it and just run it every time I think about using password login. Next time I need to ssh, I know the password login is not necessary.

sshpass -p 'PASSWORD' ssh USER@IP.ADDRESS "echo '`cat ~/.ssh/id_rsa.pub`' > ~/.ssh/authorized_keys && echo 'Match User !root
PasswordAuthentication no
Match all' > /etc/ssh/sshd_config' && exit" && ssh USER@IP.ADDRESS

At the next reboot, your system will now only accept key logins, except for root. I hope the root user password is secure. I don't require it for root because if a hacker does gain shell access, a password(or priv esc exploit) is all they need to gain root shell. It is also a safety net in case you need to login and lost your private key.

Yeah, that's not a good reason.

It's much easier to authorize a key than to input your password on every kind of interaction.

Tell me

Did you read my message? After one failed attempt you will get banned.