If you have had a potential change in your biomechanics i.e. surgery, extreme body weight change, foot growth etc, it is best to make an appointment for a re-assessment. If you wish to change the dimensions or features of the orthotics such as creating a slim-line device, extra layers of paddings etc, then it is also best to bring your footwear to the consultation and discuss these changes with your practitioner before ordering your new pair.