As the total delivery time of glasses includes production time and shipping time.
A complex prescription or lenses can cause a delay in manufacturing. Questions of your order cause a delay in production as well, especially when your prescription is incomplete and inaccurate.
Holidays in your country can cause a delivery delay as there will be a huge number of parcels in the warehouse.
In addition, some global issues may affect production and shipment, such as covid-19. As for this matter, Zinff is doing our best to offer you a safe and stable service.