By all means, have a separate, passphrase-protected key for each separate device (desktop, laptop, tablet) and push them to your machines using something like chef and the 'users' and 'sudo' community cookbooks, at a minimum, and destroy the .pem after you initially set up the host.

There is a reason that Amazon only configures one user with only one key, and it's not because that's how sane people access their machine.

Here's a better idea. Learn to use IAM properly and rotate your keys on a schedule.

You're thinking of AWS access keys. Not the same thing.

Oh, I thought this article was about AWS not SSH. My bad. Yeah, don't rotate your SSH keys either.

IAM rotates ssh keys?