Do I have to enter information into Budget Forward every time I pay a bill or make a purchase?

No, the idea of Budget Forward is to only enter information when it either deviates from your plan, or when you are specifically tracking spend as an allowance in it's own pocket account.

One of the things we tried to avoid with Budget Forward was the need to do accounting style "reconcilliation" of accounts. While Budget Forward does allow you to track the balance of each of your accounts and monitor income and expenses, it is not an accounting system.