Bitcoin wallets are protected with passwords for more security, you can even take a backup of your wallet in .dat format if you ever need it. But, a problem can arrive if you lost the password.
Hopefully,  you don't actually need to worry much as there are some scripts which you can perform on your PC which can take out the password from .dat file. This can save your wallet and your life actually, simple googling will get you many of these scripts.
But, it is recommended that you always remember your wallet password for being hassle free.