One thing to consider when handing over a product from development to production is to think about the person that will be assembling the device. During development, the product is generally being assembled by the engineers that are coming up with the design. As a result, the SOP which provides the instruction for the assembly may contain a lot of technical language which an operator on the production floor may not understand. So, SOPs should be written with clear and concise steps that are easy to follow. Sometimes it is much easier to write the instruction using pictures or a schematic rather than a paragraph explaining everything. Above all, the goal is to have a final product which is consistently well made according to the design.