The most direct measure is whether the system maps to a quantifiable business outcome—for example, reducing labor costs in a specific process, shortening the cycle from quotation to payment, or reducing a recurring error from ten occurrences per month to zero. If you cannot articulate this, or can only point to directional benefits like "more accurate data" or "better process visibility," the implementation is not yet mature. It is recommended to define what "success looks like" before implementation: which metric do you expect to change in three months? By how much? You can then compare it against your current baseline. If you cannot define this in advance, it will be difficult to justify the investment afterward.