What are the things to look for while buying a refurbished iPad?

For information, here is a list of the highest version of iOS supported by the older models of iPad (for simplicity - “generations” are shortened to a number) that are restricted in their ability to be updated:

32-bit devices (obsolete)

iPad1 - iOS 5.1.1

iPad2, iPad3 and iPad mini1 - iOS 9.3.5 (WiFi Only models), iOS 9.3.6 (WiFi+Cellular)

iPad4 - iOS 10.3.3 (WiFi Only), iOS 10.3.4 (WiFi+Cellular)

64-bit devices

iPad Air1*, iPad mini2 and iPad mini3* - iOS 12.5.7

iPad Air2, iPad mini4 - iPadOS 15.8.3

iPad5, iPad Pro (9.7"/12.9" first generation) - iPadOS 16.7.10

(*) obsolete

Newer models are all able to be updated to the current version - iPadOS 17.6.1

• iPad Pro 13" (M4)
• iPad Pro 12.9" (2nd generation and later)
• iPad Pro 11" (1st generation and later + M4)
• iPad Pro 10.5"
• iPad Air (3rd generation and later + M2)
• iPad (6th generation and later)
• iPad mini (5th generation and later)

iPadOS 18, due for imminent release, is supported by these models of iPad:

For immediate future-proofing, you might be best advised to only consider one of the models that will support iPadOS 18 - or, at the very least, a model that supports iPadOS 17.x.

Many mainstream App Developers only support the current and perhaps one or two prior major version of iOS/iPadOS.

The first consideration is the fact that Apple devices are in such demand that there are hordes of unscrupulous "sellers" of used Apple device out there trying to cash in. Only buy Apple-direct for a proper refurb.

I could make a book from all the posts here from people who bought a "refurb" from a non-Apple source only to find it was not refurbed, not properly prepared for resale and, as a result, was useless to the new owner.

Good read here: The All Too Common SAD Reality of Buying … - Apple Community

Not all countries/regions have access to Apple-direct refurbished devices. To find out if you have access, scroll to the bottom of your country's Apple home page and look for this in the small-font links at the page bottom:

If you are looking for cheapest and on time version from offered by Apple the best is 9th Gen with Apple Pencil Support and still supported by newest iOS 18. Below list of compatibile iOS devices:

• iPad Pro (M4)
• iPad Pro 12.9-inch (3rd generation and later)
• iPad Pro 11-inch (1st generation and later)
• iPad Air (M2)
• iPad Air (3rd generation and later)
• iPad (7th generation and later)
• iPad mini (5th generation and later)

Try checking out this site Refurbished iPad Deals - Apple

Hope this helps!