How to disable all password prompts?
Run as root? (Just kidding, you shouldn't do this.)
Others might have a way to do this, but I think you should consider not doing it. The permission scheme set up on Linux systems has been very well thought out, and it goes deep into the system. You can really do a lot of damage to your system very easily, and the point of having you enter a password is to make sure you want change your system in some way.
Another possibility is that some malicious piece of software tries to damage your system. This has been a huge problem on Windows systems for years. On Linux, it's very difficult to do something like this because all major changes to your system need to be authenticated.
In the end, how often do you need to enter your password? Installing software should only happen once, and then it's set up. You'll need it to make changes to the system, but again, you're probably not going to do this very often and it's easy to make a typo and break your system.
In the end, it's up to you, but I urge you to consider how inconvenient entering a password is, and how much you gain from having that extra layer of security.