The future of training involves simulation, which is often delivered by Commercial Off-The-Shelf (COTS) products. This principle was embraced by the United Kingdom (UK) Ministry of Defence (MOD) in 2010, under its Strategic Defence and Security Review (SDSR), and heralded the beginning of a paradigm shift in the way the MOD customer viewed simulation and COTS solutions. Given budgetary constraints and the need for a flexible, adaptive training capability in support of future military operations, the commitment to embrace COTS is a bold and sound step. However, whilst COTS offers obvious advantages, there is a perception that COTS provides the entire answer, and that procuring a training capability is as simple as walking into a store, picking a training solution from the shelf, taking it home and plugging it in. Unfortunately, although this approach can work for commodity items, it's not always suitable as the basis for developing mission-critical training capability. In particular, the technical specification or level of innovation in an COTS product are not the only things that customers should consider when contemplating their options. They need to ask if they have considered the implications for meeting the training objectives, technical integration, safety, business or procurement or commercial processes, and legislative compliance. Does the training task really need a 6 Degree of Freedom motion platform? Does a foreign product meet your country's safety legislation? Can the product be easily integrated with existing solutions? Asking the right questions early can save time and money and avoid disappointment. This paper reports the lessons-learnt during a series of training-related Technology Demonstrators undertaken under a MOD-funded research programme investigating COTS. The lessons are presented in a simple check-list to help providers and customers manage and mitigate risks early in planning and delivery phases, helping to maximize the benefits gained from exploiting COTS.