Inquiries in a short period of time will affect your score, again the number of points will vary by each specific situation. Generally., better scores will be less affected than lower scores, but YMMV. The credit scoring systems were not designed to factor in reward and churn behavior where someone is not actually seeking credit but miles. Overall, that population., although it seems large on this forum, is a tiny. More inquiries across a number of products in a short time frame (60-90 days) will definitely trigger a change in score. Duplicate checks by individual companies will not, as that info is not sent to the credit bureaus