Run the practice and the project
Programme, resourcing and time: the three that decide whether work lands when you said it would, and whether the people doing it are underwater.
Running a practice is mostly the management of consequences. A stage moves, and three weeks later somebody is working two weekends.
These are the capabilities that hold the relationship between the date, the person and the hour, and, through the fee, the money. They are not three separate tools that need reconciling on a Monday morning.
Try it on a real project
Free for solo practices: one user, two projects, no card.