I would say the longer that the scope remains unfinalized, the higher the chances of there being scope creep. The needs of the customer should be specified earlier on, and communication between both parties should express understanding that the design and needs of the customer are being properly understood, as well as the intentions of the product. It’s key to know what sort of applications the device might be used for in order to get a better design. The scope should be solidified as early in the planning stage as possible. I’m not sure if contracts are made, but if possible then the contract should outline an acceptable time window during which the scope can be changed if needed. If the scope changes too late into the project there will be major setbacks and possible losses. Whereas if a contract lays out the rules then it can save a lot of trouble later on in the project timeline.