Trust Center functionality and usage

Although I have used EXCEL a lot, this is my first experience with an add-in. I am told to go to the trust center settings, and then Macro settings then select "Enable all macros" and check "Trust access to the VBA project object model" click OK and close Excel. I know that this opens me up to some potential security issues. After I loaded the add-in, I went back and reset these parameters back to the way they defaulted. I am surprised that the add-in still functions after resetting the security access settings. Can I leave the settings this way? Is this what I should do to protect me from other potentially harmful macros? I am using EXCEL 2010.

Joseph -

I appreciate the quick response. All I know is that the add-in author told me to make those changes in the Trust Center in order to get the add-in to load. I made them, it loaded. I had assumed (bad thing to do) that I might have to have those parameters set that way in order to use the add-in, but in the interim I wanted to reset them back to their default (exactly equivalent to your recommendation) to help protect me against other macros that may be dangerous. I was planning to set the parameters back to where the author suggested they need to be each time I used the add-in (only once per month, so not a big deal). But I accidentally found that I could use the add-in even without doing that. So now I am assuming (here we go again) that those parameters only needed to be that way to initially load the add-in, and not for ongoing use.