Do I have to have an Apple ID for each of my devices?

Denajan ~ No, you need just one: "Use the same Apple ID everywhere you sign in to ensure that all your Apple services and devices work together seamlessly and you can access your personal content from all your devices." [Source: Apple]

...Found by searching Apple's Knowledge Base.

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If you want three completely separate devices, with completely separate iCloud storage, and each with unique local purchases and subscriptions, yes.

You might do this to keep business and personal activities completely separate, for instance.

Otherwise, no. Using the same Apple ID across all of your Macs and all of your devices is very common, a d typical.