How many devices are too many on iTunes?

Authorize your computer in iTunes - https://support.apple.com/HT201251

When you authorize your Mac or PC, you give it permission to access your music, movies, and other content.

• You can authorize up to 5 computers, which means that you can play your content on 5 different computers.

View and remove your associated devices in iTunes - Apple Support

You can have ten devices (no more than five of them computers) associated with your Apple ID and iTunes at one time.

See Authorization vs. association - Apple Community. The basic limits are five authorized computers and a mix of up to ten associated computers and devices of which no more than five are computers. Apple TV, HomePod, older iPods, etc. aren't subject to either mechanism and you can have as many of those as you like.

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