Batteries in smart keys usually last between 1 to 2 years. Unusually short battery life may be caused by electromagnetic interference. Avoid keeping your smart key near other electronic devices such as phones, laptops and other screens.
In appliances without a charging function, yes. In appliances that do have a charging function, be sure to check whether the function was specifically designed for Ni-MH. If not, it’s best not to use Ni-MH batteries.