Over the last two years, our dog has become increasingly yappy. Should we considered a training collar, or is there something else we should try?

Have you had her examined by a vet lately? I've noticed that some older dogs become more vocal due to some cognitive decline as they age. I saw this with my older Corgi towards the end of her life. She didn't exactly have dementia but she was definitely more stressed out and barky about the daily activity in our home. That would be the first place to start figuring this out. I would hate to use a corrective collar on an older dog that may be showing some type of stress without investigating throughly.

Is she crate trained or trained to stay in an ex-pen? Simply limiting her ability to move about freely in the home may make a difference also. Crating her in a calm and quiet area of the house may be helpful. I am a pretty strict dog "manager" as I have 5 dogs in the house and by limiting access to doors and windows as well as giving the dog a quiet place to relax, it can really change the vibe in the home for a dog (especially an older dog).

I hope this give you some ideas. Let me know if you have any more questions.