It’s tempting to compare the price of DJI Care Refresh with the similarly named AppleCare and AppleCare+. Like DJI’s, Apple’s scheme costs around 10% of the price of the product (see details on Apple's site), but Apple provides unlimited replacements, while the Care+ option doesn’t add time but coverage for also covers theft. Apple offer a monthly premium payment option and theoretically endless cover.
Apple’s scheme make sense for the product’s likely life, though. A better comparison might be other drone companies and 3rd party insurance.