(62)It should also be clarified that, while contracts based on a framework agreement are to be awarded before the end of the term of the framework agreement itself, the duration of the individual contracts based on a framework agreement does not need to coincide with the duration of that framework agreement, but might, as appropriate, be shorter or longer. In particular, it should be allowed to set the length of individual contracts based on a framework agreement taking account of factors such as the time needed for their performance, where maintenance of equipment with an expected useful life of more than four years is included or where extensive training of staff to perform the contract is needed. It should also be clarified that there might be exceptional cases in which the length of the framework agreements themselves should be allowed to be longer than four years. Such cases, which should be duly justified, in particular by the subject of the framework agreement, might for instance arise where economic operators need to dispose of equipment the amortisation period of which is longer than four years and which must be available at any time over the entire duration of the framework agreement.