Honestly not that much. It seems pretty lightweight. It has it’s own measurement of battery usage (can’t say how accurate it is but still better than nothing perhaps?) and on the tablet it has consumed around 9mAh, which I guess isn’t too crazy.

I’ve been using AdGuard on my phone (OnePlus 6T) and tablet (Tab S7 FE) for quite some time now. Neither device is rooted. I got AdGuard lifetime license on sale from StackSocial a while back. The app isn’t on the Play Store (if you look for it, you will instead find an extension for the Samsung browser or something). They have you download the .apk from their site, and then you can set up the blocking how you prefer. It works by setting up a local VPN. I think there’s other ways to use it but I didn’t feel the need to tweak further. Because it acts like a VPN, all app traffic flows through it so ads are blocked pretty much system-wide. Browsers, social media apps etc. Honestly I’d highly recommend it.