Google Ads
Catching people at the moment they search for what you sell.
Search advertising buys intent rather than attention. Somebody typing "emergency roof repair" has already decided. The only question left is who they reach first.
That makes account structure matter more than ad copy. Tight themes, negative keywords that actually get maintained, and landing pages answering the exact query rather than a general version of it.
The waste is nearly always in the same three places. Broad match left unattended, a landing page too slow on a phone, and conversion tracking counting the wrong thing and then optimising towards it.