BetaTesting has hundreds of targeting criteria. However, in general, we only recommend using the filters that are most critical to reaching your audience. Each additional criteria you apply exponentially limits the available audience.
There are two scenarios when a test is considered to have "Niche targeting" and costs 2X the number of credits:
Scenario 1: When defining targeting criteria, if your available audience on BetaTesting is < 1,500 people (out of 450,000+, or 0.3% of our population) it counts as "Niche targeting" and will cost 2X the number of credits. This audience size rule only applies when your invite method is set to BetaTesting Panel. If you are inviting your own testers instead, a small available audience does not make your test niche.
Scenario 2: When targeting business professional using employment industry, title, or job function criteria. This applies no matter which invite method you use.