I use only one card and it is used for several reasons.  1) benefits for air miles  2) discounts and incentives with participants 3) charge statements also provide a means to document and manage expenses (provide year end summary)  4) support provided by regarding filing a dispute on a transaction; this can put a transaction on hold until dispute is resolved   This helps if outside agency needs to intervene and you had the documentation available.  The fee charged is nominal compared to services offered.  Overall budgeting is to insure you purchase what you "need" and minimize your "wants" and leverage services.  Just saying...