A case is the overall framework around a customer or a process, an order is the concrete agreement for a piece of work, and a task is the individual action an employee actually carries out in the field. A case can contain several orders, and an order can contain several tasks. Your software needs to keep track of all three levels at once, so you can always see what belongs together, without digging through emails and spreadsheets.
A case gathers everything related to a specific customer, address, or process, no matter how many times work is carried out there. It could, for example, be a customer's property, a construction project, or an ongoing service agreement. The case provides the overview, while the individual orders and tasks sit underneath it.
An order arises once an agreement has been made for a piece of work, with a price, a scope, and typically a deadline. A work order is the unit that later forms the basis for invoicing, because it describes exactly what has been agreed and what needs to be done.
A task is the action an employee carries out in the field, for example a single visit, a repair, or a service inspection. An order can easily consist of several tasks, if the work spans multiple visits or requires several tradespeople.
If the three levels get mixed together in the system, you quickly lose track of what belongs to what, and what has actually been invoiced.
If an employee logs time and materials directly on a case instead of on the right task, it becomes difficult to see which work belongs to which agreement once the invoice needs to be created.
Good case and task management means you can move from the case down to the individual task, and back again. That makes it possible to see the full history for a customer, while each individual task can still be planned and invoiced on its own.
When time and materials are logged on the correct task, and the task is linked to the right order, the invoicing basis becomes correct automatically, without anyone having to reconcile records afterwards. If the case is a larger process with several orders, project management gives you an overview of the finances across the individual orders at the same time.
Yes, that's typically how it works. A case, for example a customer's property or a facility, can easily cover several separate orders over time, each with its own price and its own process.
No. An order is the actual agreement for the work, while a task is the concrete action carried out to fulfill the order. An order can therefore consist of several tasks.
A spreadsheet can't automatically link time tracking, materials, and documentation from the individual task up to the right order and case. That has to be done manually every time, which increases the risk of errors in the invoicing basis.
Yes, in practice it becomes necessary as soon as a customer or project generates more than one order or task. Without that separation, it quickly becomes unclear what actually belongs together, and what has already been invoiced.