You have landed a new contract and your client has agreed to pay you $5000 per month to create and run ads for him on social media.  Only $2000 of the $5000 is your management/consulting fee for the work that you will do and the other $3000 per month is for ad spend with Facebook, Google Adwords or some other platform.  With the technology available these days it is likely that the funds have been directly deposited into your bank account.  So, how are you going to keep track of the actual revenue you have earned for your services separate from the money that has been provided for ad spend?