You can set your Mac to not require a password when you start up, wake up or log in. However, you should never use this function. Doing so leaves all of your information vulnerable to anyone who gets physical access to your Mac. Even if you are using a Mac that is stationary and locked up, it doesn't make sense to take the risk. Entering a password every time you use your Mac is a small price to pay for good security. You can mitigate the number of times you enter your password by setting the Require Password time to something reasonable, such as 5 minutes.