Smaller, tightly grouped ad groups tend to work better because you can write ads that closely match the keywords inside them. When an ad matches what someone searched for, it usually gets a better Quality Score, which can lower your cost per click. Larger ad groups with many different keywords often lead to generic ads that do not speak directly to what the user wants. That said, managing many small ad groups takes more time and effort. So which do you think works better in practice, many small ad groups or fewer larger ones?