It is the last working day of the month. The service manager has a spreadsheet open beside the service desk. Column A is the technician, column B the ticket, column C the hours they remembered to log, and column D the rate, which depends on which contract the client is on and whether the work was after hours. Three clients have two contracts each. Two technicians logged time against the wrong client. One ticket from the twelfth was billed last month and is about to go out again. By five o’clock the invoices are in the accounting system, and nobody is confident they are right.
Because the hours live in one tool and the rates live in another, and a person carries them across. Time is logged in the service desk, if it is logged at all. Contract rates are in a document, a spreadsheet or the accounting system. The invoice is assembled by looking one up against the other, and every lookup is a chance to pick the wrong rate, miss an hour or bill it twice. The work is not hard. It is tedious, it is monthly, and its errors are found by the client.
In Guardian PSA, time is tracked on the ticket as the work happens, against the client and the contract the ticket already belongs to. At month-end you generate invoices from that time, grouped by contract, at the rate that contract carries. Anything the contract cannot price is listed and explained rather than silently dropped. Each entry that goes onto an invoice is stamped as billed, so the same hour cannot go out twice.
The third line is the one that matters. A tool that drops what it cannot price produces an invoice that looks clean and is wrong. A tool that lists it and says why gives the service manager a short list to decide on: add a rate to the contract, write it off, or bill it by hand. The decision takes a minute because the question is already framed.
The stamp. Once a time entry is on an invoice it carries that fact, and the next run does not pick it up. This sounds small until you have found a duplicate the hard way, which is usually when a client’s finance team finds it for you. The ticket from the twelfth in the scenario above would not have appeared in the September run, because it was stamped in August.
Into the books you already keep. Guardian PSA does not try to be your accounting system. Invoices carry an external reference so they line up with whatever you run your books in, and QuickBooks Online is where they go to be sent and collected. Contracts themselves go out for signature through DocuSign. The desk owns the time and the rate; your accountant owns the ledger.
From the contract, which is a record with a life of its own rather than a PDF in a folder. Contracts in Guardian PSA move through lifecycle stages with full version history, so the rate that was in force when the work was done is the rate that prices it. Renewal detection, notice periods and auto-renew are tracked, so the contract that expired on the ninth does not quietly price the work on the tenth. Churn reasons are captured when a client leaves, and health scoring runs across the book of business, which is a longer story than billing but starts from the same record.
Projects bill from the same time. A sprint has a real close ceremony rather than a status flip; dependencies, epics, story points and subtasks are tracked; cycle time, cumulative flow and estimation accuracy are measured; and every carried-over item is logged, so spillover is visible rather than a feeling. Time against a project ticket prices at the project rate, as the second line of the example shows.
One working day per month for whoever assembles the invoices, plus the minutes each technician spends reconstructing time they did not log while the ticket was open. Then the credit notes: every duplicate hour and every wrong rate is a conversation with a client about money, and those conversations cost more than the amount on the line.
Devices, people, modules and term. The number comes from that, and so does an honest answer about your month-end.