Whilst there is always guidance and information about evacuation equipment available - the type, quantity and location should be your decision as a result of your risk assessment and professional advice, not an overzealous salesman.
We have helped many clients save thousands of pounds while ensuring they maintain compliance. One example is a University with 330 operational buildings. Previously they had evacuation chairs in every building with a lift on virtually every staircase. Due to the age of the chairs, the University was seeking options for replacements. We performed a free audit and working with various University stakeholders we reduced the number of chairs to a fraction of what was already in place. In addition to the savings on equipment a compliance package was included to cover supply, installation, certificated evacuation chair training, refresher training and evacuation chair maintenance.