In practice, software testing consists in the process of examining the provided product, searching for defects based on the specification, common sense and experience of the worker. There are quite often cases when testing is carried out only on the basis of the tester's experience, such testing is sometimes called exploratory testing, sometimes ad-hoc testing. The main advantage of such testing is that the employee is left to himself and all work is based on his assumption of a quality product. On the other hand, such testing can lead to large time costs, a distorted final result, especially in cases where the tester does not have sufficient experience. If you want to find good software testers, I advise you to check out this company savarian.tech/services/software-testing-company . They have 8 years of experience in this field, so I'm sure they can help you.