Online machine translation services offer affordable, high-quality translations. Translation providers want to use the best MT for their customers and freelancers. However, it is difficult to evaluate of black-box, ever changing MT services. In this talk I discussed best practices how to efficiently conduct an evaluation of MT services for the language pairs and content you care about. I introduced the MT Decider Benchmark – a vendor-independent, transparent evaluation of 4 major online MT services for 24 language pairs.