The only channel where they asked first.

Once you have solid conversion data and a mature negative list, it can find valuable searches you would never have listed. In a new account with neither, it is the fastest way to waste a budget. Earn the freedom rather than starting with it.

Fewer than most accounts contain. Tight groups where keywords genuinely share a meaning let the ad speak precisely to the search. Accounts with hundreds of loosely related keywords in one group produce generic ads and poor relevance scores.

It varies enormously by industry and by how commercial the search is, so a benchmark is less useful than it sounds. What matters more is the relationship between clicks, cost and enquiries — a high click-through rate on searches that never convert is an expensive success.

Usually yes, and it is cheap because your relevance is perfect. It stops competitors appearing above you on your own name, and it lets you control the message. The counter-argument — that you would have got the click anyway — is sometimes right, and it is testable.

Competition, and relevance. You control the second: a tighter keyword group, an ad that matches the search, and a landing page that matches the ad all reduce what you pay per click. Improving relevance is usually cheaper than raising bids.

Weekly at minimum while a campaign is young, then at least monthly. New search terms appear constantly as language and demand shift. An account whose negative list has not changed in six months is not being managed.