Most password managers provide apps and syncing, and are often integrated into your browser, so everything is a click away. Having to juggle 4 emails, remember which of 5 passwords a site uses, and figure out your exposure in case of a breach seems a lot harder than the above.

I happen to use the open source password manager from Keepass.info. It works on a local password file protected by strong crypto. Then, I use Dropbox to sync that file from device to device.

The problem with using the same password on multiple sites is this: if any one site gets pwnd, it gets a lot easier for the cybercreeps to pwn your account on other sites (says Obvious Man).

It doesn't take much technical skill to credential-stuff--to hammer a lot of sites with a list of credentials. So, keeping the list of sites you actually use a secret is not effective.

This whole deal sucks. But it's real.

Personally, I use LastPass across browsers in multiple desktop accounts and my mobile browser, with no issue. You create a LastPass account, presumably with a very secure password, that you can log into elsewhere.

As for the password strategy, I imagine you could be vulnerable if any two important accounts - say, email and bank - both used the same password. Are you confident this is not the case?

I assume certain emails associate with certain types of accounts, which could flaw your strategy. If you're able to remember ~15 different passwords with random emails, congrats on your stellar memory!

I use Google Smartlock, and it functions across all my (android) devices quite well. It does sort of rely on your being all-in on the Google ecosystem. At work we use LastPass, but since I only use it on the desktop in a browser I can't speak to how it works across devices.

LastPass works for multiple devices, including mobile - you can sync to 1 LastPass account, too.

Does smartlock work with native mobile apps (which may or may not use magic webviee for auth), or is there a way to manually transfer password to log into an app?

Password managers across devices:

Either use a service that syncs up to a server, or a standalone apps and save its encrypted database to a shared filesystem such as Dropbox or pcloud.

As long as you don't care if at most 4 of your accounts get hacked, then you have an effective strategy, I guess.