In SAP, both internal orders and projects are commonly used for control of project expenditure. Both operate as primary cost collectors to monitor projects expenditure to budget. Planned expenditure can be forecast for both internal orders and projects, and the final project costs can be settled to produced fixed assets. For consistency, many organizations choose either internal orders or projects. Internal orders are more simple to set-up, use and report on. If most of your capital expenditure involves direct asset purchases (for example, new forklifts), internal orders are normally sufficient.
Projects provide for more granular cost control and scheduling. If you execute higher-value projects that may involve creation of multiple assets or that span multiple periods (for example, a new manufacturing plant), use of projects is highly recommended. Ideally, your capital expenditure management process should be flexible enough to use both objects: providing simplicity when sufficient, and complexity where required.