A purchase creates a client, with the hours they bought on their balance. You can also add a client by hand, for someone who paid you another way.
The balance
Hours in, hours out. Buying adds to it. Logging time takes from it. What is left is what they have in hand.
A client can go overdrawn if you log more than they bought. That is allowed, because the work happened. It is flagged, because it needs a conversation.
Squaring up
When a client is overdrawn and Stripe is connected, their hours tab has Square up. It makes a link to a page on your site that asks for exactly what they owe: the hours over, at your rate, fixed when the link is made. Send it however you like. When they pay, the hours go back on and the balance is zero.
It is not an invoice. One line, no invoice number, no due date. A new link replaces the old one, so a client never holds two for the same hours.
Adjusting a balance
Add hours credits time without a purchase: a goodwill hour, a correction, work agreed elsewhere. Every adjustment takes a reason, and the reason is kept. If a number moved, the record says why.
Opening hours
A client added by hand can start with a balance, so an existing client can be brought in without a made-up purchase.
Notes and their own rate
Each client has notes, and can have their own hourly rate. That is how you charge two clients different rates without either seeing the other's.
Archiving and deleting
Archive a client when the work stops. They leave the active list and their history stays. Deleting is for good, and asks twice.
A client who has paid you cannot be deleted. Their purchases are your books. Archiving already takes them off every list.