Apple watch repair option

Depending on the damage of your Apple Watch, the cost for labour and parts may exceed a certain amount of money, that makes a replacement more reasonable.

If your watch is replaced by Apple and you pay the service fee, you will get in most cases a refurbished watch, which has a new battery, new glass and buttons, seals, etc. And it also comes with a short warranty period.

Apple Watch Service and Repair - Apple Support

Most third party repair shops have unoriginal parts, which could interfere with the functions of the Apple Watch. Hence why Apple advices not to get your iPhone fixed at the third party store. Only Apple stores and Apple authorized repair shops. I hope this helps!