How can quality inspection services be carried out by the third parties to ensure that the wholesale orders are not defective?

A nightmare indeed is getting burnt by faulty inventory on huge manufacturing runs abroad. I'm learning the hard way that looking at factory photos for inspection alone isn't sufficient when scaling up purchase orders. I would like to create a more robust quality control system, incorporating third-party quality checks before shipping.

I've considered enterprise companies such as SGS, and digital inspection platforms such as TradeAider or QIMA, but prices and turnaround times are very unpredictable. The prices of basic pre-shipment inspections vary greatly, for example, with some providers coming in at $148 per man-day and others at more than $300.

What kind of inspection/certification services do you use regularly for your supply chain and how does their pricing and report speed model work in reality?