It is good to review the warranty and have the batteries replaced before it ends. Your audiologist may not tell you this. The cost to replace outside of warranty can be up to $350 for each hearing aid. It takes about two weeks or a bit less. Your audiologist should be able to loan you a set of hearing aids for free to use while you wait. There is a one year warranty with the replaced batteries.
There is also the possibility of extending the original hearing aid warranty for a year but check out the deductible if you need to use it. My rechargeable hearing aids are covered for loss through my homeowners insurance for a minor additional cost that is way less than offered by the audiologist practice.