This paper studies the simultaneous optimisation of quality and costs in mass-production of complex electronics products. Testing has become a critical bottleneck for assuring quality, requiring a large amount of time, and resources. The volume of especially functional testing must be minimised to reduce costs. Sampling is a potential way to obtain this. Unfortunately, existing sampling methods are not functional in the modern electronics environment with multiple tests. This paper presents new efficient methods, based on continuous sampling plan (CSP) procedures. The applicability of the developed methods is confirmed empirically by analysing and simulating real industrial data.