Programs are increasingly turning to COTS assemblies in order to gain timely access to the latest technology under favourable commercial terms. There is a potential downside though in that by design COTS building blocks utilize commercially available components, the availability of which is governed by wider market forces. As a result, in order to guarantee supply, it is vital that any COTS procurement is supported by a Long Term Support strategy appropriate to the program. In part this strategy has to mitigate, or even eliminate, the effects of obsolescence but it also has to address all factors required to support maintenance, repair and upgrades to fielded equipment. This paper will explore a range of techniques that when added together as part of a coherent strategy can provide Long Term Support tailored to program timescale and financial needs.