I am using a program (1Password in my case), which will generate passwords. These passwords are stored in an encrypted vault with a master password. This vault is synced to a cloud location (like Dropbox) and I have that program on two PCs, my phone and tablet, all setup to sync from the cloud location. On phone and tablet the vault can be unlock with fingerprints, which makes it quick.
These passwords are not guessable and no password is used twice. Have to change password in a browser? Right click the password field and select generate password.