When you deal with a lot of computers and networks you have a very large list of passwords you need to remember. You can set them all the same but that would be a security risk, all you would need is for one place to compromise your password and everything would be exposed. I use the program Keepass to keep my passwords secure.
There is a version of Keepass on every operating system so no matter what you are using you will be able to work with your passwords. I use Dropbox to keep the password database file in sync across all of my devices and computers. That means as soon as I add a new password I can then access it anywhere I would need to.
The passwords database is password protected and can be setup to use a key file as well. If you want to use Dropbox to sync the password database file then I recommend using a key file which is not stored in your Dropbox EVER (Dropbox keeps files which have been in it even temporarily forever unless you go into the website and delete the deleted files).
What I find very useful is that you can store the login URL of the passwords so you can open the URL and use the programs auto type your password so it never even has to be exposed on the screen.
Another feature I really like about this application is that it can be used to generate completely random passwords. It will then save them in the database entry for the password you are creating.