Apple recently extended their service policy for the 1st generation Apple Watch from 2 years to 3 years from the purchase date against defects from the back cover coming off. Although their policy was updated, it was not publicly announced, remaining mostly unknown to most consumers and even some Apple employees.
The defect as mentioned by many users claim that their Apple Watch's back cover would come off after pulling it off their Apple Watch Accessories, like their magnetic chargers leading to unusable functions like the heart rate monitor.
"Apple has determined that under certain conditions on some Apple Watch (1st generation) devices the back cover may separate from the watch case. Apple will service eligible devices free of charge. Apple will authorize coverage for three (3) years from the date of purchase."
If you are an owner of the 1st generation Apple Watch, and are experiencing this issue, please feel free to contact the Apple Genius Bar to set an appointment for a free repair. You may also visit an authorized Apple Service Provider as well.
If you have experienced the back cover coming off in the past, and have paid for the repair, you may be eligible for a refund. You may inquire about the refund by contacting Apple Support.
Remember, this policy has not been publicly announced, so for the time being most people remain unaware of this. If you are experiencing the back cover defect on your Apple Watch, be sure to request your free service repair or request one directly from a manager.