If a specification is older than 5 years, it is probably outdated or inaccurate.
If you are reusing specifications from old projects or tenders, make sure you check that the information in them is still current.
Sometimes a client will send you a specification that is from their files from previous projects. It can often be outdated information and needs to be checked that it matches the current standard or expectation.
For example, the electrical wiring might be specified to be a certain colour, yet new standards call for different colours. If you are supplying those specifications to a contractor, you would be responsible for specifying the correct colour; otherwise the contractor may install the wrong colour and ask for a variation to rectify it.