Single sign on solutions don't work when some of the systems you sign on to are air-gapped and will never, ever, EVER be connected to any network. Other networks I access are completely separated from the greater internet. It would be useful, but single sign on would take my 25-30 passwords and shrink it to about 15.

Which would be useful but would still require me to keep track of them manually.

In those cases people should be using hardware authentication tokens. They're both more usable and more secure.

Try convincing the US government of that. I wish you luck (I really do). Trying to educate program security people on computers is one of the banes of my existence.

Plenty of parts of the US government do know. I've seen multiple DoD networks where hardware tokens are the required form of authentication.

So have I. CACs don't work on classified systems though.

These don't work on all networks. Like classified networks.

I have one password for the Corporation (email, VPN, various online databases, dashboards and wikis). I have another one just for requesting vacation time, because that system is run by the Corporation that owns the Corporation I work for.

Then there's the password for timecards (outsourced to another company), goal setting and training (outsource to another company), 401k, medical insurance and just because, another company (that isn't our medical insurance) for handling prescriptions.

Our Corporation has one password expiration timeframe (90 days but not really because they start nagging two weeks prior and won't shut up until you change the password) and the Corporation that owns The Corporation has another timeframe (60 days, but again, they start bitching about two weeks prior) and of course, all these sites have their own ideas about "secure passwords."

Weren't certificates supposed to deal with all this?

Wait ... don't answer that. I don't think I want to know the answer.

You know what's better than single-signon? Two SSO systems! It's fantastic. Not only do you have to remember which backend each system uses, but it actually makes it harder to remember passwords for systems that don't use SSO.

Especially the ones that are used irregularly (annually, quarterly), so SSO isn't a priority.

My passwords are all on a whiteboard by my desk.