Save ad settings with browser plugin
A companion to signed-out Ads Settings
It's most common to turn Google ad personalisation on or off with Google's Ads Settings. These settings are saved to your Google Account (if you're signed in), or to your browser (if you're not signed in).
Alternatively, you can install a browser plugin to keep your preference to opt out of personalised ads.
Turning off ad personalisation doesn't remove ads
If you use this browser plugin, the same number of ads will appear on websites that you look at. The plugin turns off ads personalisation. Turning off personalisation makes ads less relevant to you.