Expensive verticals punish broad targeting fastest.
In UK legal, insurance, finance, private healthcare, B2B software and the trades, a single click on a high-intent term can cost several pounds, and phrase-adjacent junk costs the same as the term you wanted. That means a £1,500 or £3,000 monthly budget cannot be spread thinly across the whole country and every keyword theme at once — it buys a handful of clicks per term and never reaches enough conversions to teach the bidding algorithm anything. The workable route is to narrow first: a short list of terms with genuine commercial intent, tight geography, aggressive negatives, and one landing page written for the query. Volume comes after the account can prove what a qualified enquiry costs, not before.