sudo is a security measure to allow the Linux system to be more secure by allowing access to the
In order to prevent users from accidentally (or maliciously) damaging a Linux system, the
root account was created in order to separate and protect some system actions, like raw filesystem access and editing (or even seeing) critical system and service files.
However, just allowing raw access to
root by way of a password is considered unsafe. Therefore, the account is "disabled" and was moved to more of a virtual role wherein it can only be accessed by either the system itself or any user who has sudo powers, as determined by the
/etc/sudoers config file.
sudo "remembering" your password is a convenience feature more than anything. You don't have root, as much as you've had root recently in the past, therefore the system trusts you. You can, of course, decrease this time or disable this feature altogether, but that seems unnecessary.
If you're using
sudo for something very frequently, it may be worth changing permissions and the like to allow you to not use
sudo, but you need to be careful with this. Changing the permissions for the wrong file can completely destroy your system and prevent you from even booting.