I have a whole house surge protector, surge protector for the A/V equipment and surge protector for the washed and dryer with all their electronics. I just had an wireless alarm installed that has a 16.5 volt wall wart. Protect it too?

 

if you already have a whole house surge protector, then anything you plug in anywhere in the house is in theory already protected...

 

Yes and no; surges from outside are stopped, but and internal surge from an appliance not so much.