Buy a new Apple Watch or just replace its battery?

Apple Watch batteries use lithium-ion technology. Compared with older generations of battery technology, lithium-ion batteries charge faster, last longer, and have a higher power density for more battery life in a lighter package. Of course, all rechargeable batteries are consumable components that become less effective as they chemically age.So, when you Apple Watch won’t hold a charge for as long as it used to, should you buy a new Apple Watch or just replace its battery?
Apple Watch Ser