When people search for your client’s watch repair business, they use very specific terms like “vintage watch repairs”. To show your ads for these searches, you’ll want to use:
- Negative match keywords
- Broad match keywords
- Exact match keywords
- Phrase match keywords
In general, the broader the keyword matching option, the more traffic potential that keyword has. Conversely, the narrower the keyword matching option, the more relevant that keyword will be to someone’s search. Understanding these differences can help you to choose the right options and improve your return on investment. “Very specific terms” in question indicates Exact match Keywords. However from my practice it’s much wiser to have Exact, phrase and broad match types of keyword in a single ad group.
A keyword setting that allows your ad to show only when someone searches for the exact phrase of your keyword or close variations of the exact phrase of your keyword. The exact match keyword “bicycle bell” can cause your ad to show only if someone searches for “bicycle bell” or close variations of “bicycle bell” exactly, with no other words.
Read more here: https://support.google.com/adwords/answer/2407781?hl=en