Hourly billing refers to a pricing model used by some law firms, consultancies or other professional service providers where they charge their clients on an hourly basis for the time spent working on their behalf. This means that the client is billed in increments of one hour and the total amount charged depends on how much time was actually spent on the project. Hourly billing can be used as a way to measure productivity, ensure accountability or provide transparency for clients who want to know exactly what they are paying for. However, it is not without its critics who argue that it encourages inefficiency and drives up costs.