The number of credits needed varies by service.
For example, to provide a bid on a pet photography project it could be as low as 3 credits, whereas managing a home construction project could be as much as 20.
Since there can be several professionals bidding on each job, it means that it is unlikely for a professional to win every job that they bid on. The prices that we charge to bid are reflective of this. To maximise your chances of winning, please read What Makes a Great Bid.