Determining how much bandwidth your business needs depends on many factors including number of employees, as well as the type of internet operations your employees use. The following operations affect bandwidth: email, cloud services, online banking, VoIP, uploading and downloading files, web browsing, remote access, video conferencing.
Light usage would be basic email and web browsing. Moderate usage would add file downloading, streaming music/video, using the cloud, and VoIP. Strong delivers all of the above plus large file downloads and interactive web conferencing. Heavy usage covers the same as strong plus additional high bandwidth demand, heavy use of internet applications and multiple devices per user.