Quick answer
Broad, phrase and exact match are not three completely separate keyword universes. Google uses matching systems to interpret intent, and the practical control layer is the combination of match type, negative keywords, search-term review, landing-page relevance and conversion signals.
Choose the level of discovery you can responsibly monitor. Broad matching can uncover useful demand, but it also makes conversion quality and negative-keyword management more important.
What I would check first
I would inspect the search-term report rather than guessing what a keyword means. Look for irrelevant themes, different buying stages, competitor searches, research-only queries and terms that produce leads that sales cannot use.
I would also check whether conversion tracking is strong enough to distinguish useful demand. If every form fill is counted equally, broader matching can appear better than it really is.
Decision framework
Use narrower matching when a theme has proven commercial value and the business needs tighter control. Use broader discovery when there is enough signal, a clear negative-keyword process and a willingness to evaluate actual search terms.
For a plumber, 'emergency pipe repair' can be a strong commercial theme while 'how to repair a leaking pipe' is informational. The latter may be useful for SEO but is not automatically a good paid-search target.
Implementation steps
Group keywords by intent rather than stuffing dozens of near-duplicates into separate ad groups. Write ad and landing-page messaging around the problem being solved, then review actual search terms and add negative themes systematically.
Keep a change log. When match settings, negatives or bidding change, note the date so later performance analysis has context.
Common mistakes and current platform considerations
Do not assume exact match means the ad will only show for one literal query, and do not use large keyword lists as a substitute for search-term analysis.
Google's current Search automation increasingly uses intent and context rather than literal string matching. That makes the search-term report, conversion quality and negative controls more important than old-school keyword-count thinking.
Measurement and business implications
Measure qualified conversion rate and cost by search-theme, not just by keyword. A theme that produces fewer leads but substantially better customers can be more valuable than a high-volume theme.
Pair this guide with the Google Ads beginner guide and the Google Ads Performance Calculator. Use the Google Ads Search Ad Builder and Launch Checklist during implementation.