What do you guys do about usernames / passwords for your local services?

Basically every local service is accessed via a web interface, and every interface wants a username and password. Assuming none of these services are exposed to the internet, how much effort do you put into security here?
Personally, I didn't really think about it when I started. I make a half-assed effort at security where I don't use "admin" or anything obvious as the username, and I use a decent-but-not-industrial password - but I started reusing the u/p as the number of services I'm running grew. I have my browsers remember the u/ps.
Should one go farther than this? And if so, what's the threat model? Is there an easier way?