That &quot;ratcheting effect&quot; is by design.<p>Similarly, anti-virus software has a &quot;ratcheting effect&quot; in that once you install them, you don&#x27;t get to see the kind of high-quality viruses and trojans that might convince your computer to encrypt all your files or give up your bank passwords.<p>Installing an ad blocker has become another one of those &quot;hygiene&quot; steps that you do whenever you set up a new PC: Install Anti-virus, install OS-provided updates, install ad-blocker.