How many iPads can I add to one account

"When you turn on iTunes Match, Family Sharing, or Automatic Downloads, or when you download past purchases on your computer, iPhone, iPad, or iPod touch, that device becomes associated with your Apple ID. You can associate your Apple ID with up to 10 devices, with a maximum of 5 computers at any time. Each computer must also be authorized using the same Apple ID. You don't need to authorize your iPhone, iPad, or iPod touch."

Manage your associated devices in iTunes - Apple Support

When an employee returns a device, make sure the device isn't tied to an apple id.

For larger numbers, it may be worth it to invested the time in a MDM, Mobile Device Management.

"This document offers guidance on some important considerations for getting the most out of your iOS deployment." Covers: Prepare your infrastructure. Set up devices. Configure and manage devices. Deploy apps and content. Plan for support.

https://www.apple.com/ipad/business/docs/iOS_Enterprise_Deployment_Overview_EN_F eb14.pdf

Quick overview of zero-touch MDM enrollment, DEP

http://www.apple.com/education/it/dep/

Consider DEP, Device Enrollment Program. Use VPP, Volume Purchase Program. Select an MDM, Mobile Device Management. Read the Google doc below and nsdjoey write up.

IT Resources -- ios & OS X -- This is a fantastic web page. I like the education site over the business site.

View documentation, video tutorials, and web pages to help IT professionals develop and deploy education solutions.

Education

http://www.apple.com/education/it/

business site is:

https://developer.apple.com/enterprise/

http://images.apple.com/lae/business/docs/iOS_Enterprise_Deployment_Overview_EN_ Sep14.pdf

MDM -- Mobile Device Management

For a comparison see this page:

http://www.enterpriseios.com/wiki/Comparison_MDM_Providers

VPP -- Volume Purchase Program

http://www.apple.com/education/it/vpp/

Copyright restrictions still apply. Either one person is the exclusive user of several devices thus have access all apps on bought by the person. Or, any number can share the same device, but the apps cannot be shared with more than one iDevice.

Robert