We've got an older German Wirehaired Pointer, she's 13 and was a rescue. In typical pointer fashion, she's extremely fit and active with no aches and pains, although her hearing and eyesight aren't what they were.
I have heard from a few dog owners that a good time to get a puppy is when your existing dog is a bit older- modeling good behaviours, etc? But I wonder if she would just feel horrified at a bitey, enthusiastic interloper. She's had a rough ride over her life and had horrific separation anxiety when we got her (now totally overcome, but it took years).
Just wondering what the doghouse wisdom and experience on the matter was.