Typical Maintenance Costs For Cameras And VMS

Would anyone like to share what they believe to be typical maintenance costs paid to vendors to receive phone tech support and firmware updates for cameras and VMS systems? For VMS systems, cost or percentage of cost of channel/camera license is fine and for cameras, percentage of purchase cost is also fine. If you want to share specific examples, that's fine, or if you would rather not mention vendors, that's fine as well.

Thanks!