An inspection is an observation at a point in time, made on part of a consignment, and written down in a form someone else can read later. It is not a certificate, it is not a legal opinion, and it does not turn a weak specification into a strong one. Buyers who get value from an inspection are usually the ones who decided in advance what would be checked, what would be accepted, and what they would do with a result they did not like.
The scope is agreed before the visit, not after it. A workable checklist names the checkpoints in the order a person would work through them: quantity produced and packed, workmanship against the approved sample, measurements against the specification, function where the product can be operated, packaging and carton marking, labelling, accessories, and the condition of the outer cartons. The sampling plan belongs in the same document. How many cartons were opened, how many units were taken from each, and how the units were chosen should be fixed in advance, because that decision is what allows two visits to be compared. The report should state the plan and the quantities actually inspected, so a reader can see the difference between a full count and a sample.
What falls outside is as important as what falls inside. Units that were not sampled were not seen. Faults that appear only after use, faults hidden inside a sealed unit, and damage that happens after the cartons leave the loading dock are outside the visit. So is the supplier's internal process, and so is the question of whether the goods satisfy any rule of the destination country. The visit also does not decide who pays for rework or for a delay; that rests on what the purchase order says, which is why a report is most useful when the purchase order already states what happens if a checkpoint fails.
Timing changes what the inspection can still achieve. A visit during production can catch a problem while there is still time to correct it and before the full quantity is made. A visit at the packing stage sees the goods as they will travel, and still allows a corrective round to be finished before the container is sealed. Whoever attends matters as well: the person from the factory who can open, move and explain the goods, and the person from the buying side who can answer a question on the spot. Before the visit, send the specification, the approved sample details, the packing list and photographs from the previous shipment if there was one.
Then read the report for what it is. It should give the date and place of the visit, the quantities, each checkpoint with its result, including the ones that passed, the photographs that support them, and a list of items that need an answer from the supplier. A report that lists only failures cannot be compared with the next visit and cannot tell you whether the rest of the order was as expected. Decide before the visit what you will do with each kind of result, so that the answer does not have to be invented on the day the report arrives.