It can be difficult to keep track of the passwords that you use. The temptation is to write them down which isn't a good idea or use the same password all the time.  An alternative and better solution is to use a Password Manager 

A password manager is a software application that helps you store and organize your passwords. Password managers usually store passwords in an encrypted database that is either stored on your computer or on the Internet.  A Master Password is used to access the password manager.  

While the core functionality of a password manager is to securely store large collections of passwords, many provide additional features such as auto-generating passwords and filling in forms.

The big advantage is that you dont need to remember individual passwords for logging into services.  

It is worthwhile looking at the different products available.   Here are a few that are worth looking at:

• Last Pass. 
  
• Dash Lane
  
• Open source, free product:  KeePass
  
• 1Password