I love that it's been so long since I've been on the forums (got roped into silly facebook horse groups and they just don't have the same community feel as there was here) and that I'm seeing familiar usernames! Love also seeing all your seniors!
I have been lucky enough to see 2 horses into their senior years, even though both were a bit close to their senior years when they came into my life.
We'll start with my first, and also heart horse who I lost far too soon and very unexpectedly 
1. Horse's name: Berry Flamable (Bear)
2. Breed: Registered Purebred Arabian (He was linebred Bask and a grandson to Huckleberry Bey).
3. Age when first owned: 16
4. Age When Passed: Less than a month into 23.
5. Pictures:
And a picture from one of our first rides.
Our last picture together at UT Animal Hospital. One of the worst days of my life and I still tear up looking at his pictures, and miss him constantly.
After losing Bear, Doc and I became extremely close, we helped each other mourn. Bear was the only horse Doc ever truly bonded with (though thankfully now I found another Arabian with a similar personality that he is bonded to now, and all is well in his world again!)
And now, my other senior horse, who thankfully is still with us, Doc!
1. Horse's name: Doc (his registered name still makes me giggle because it doesn't suit him at all, Black Market's Undertaker)
2. Breed: Registered Tennessee Walking Horse
3. Age when first owned: Knew him since he was 18, he became officially mine at 23.
4. Current Age: He'll be 27 next month!
5. Pictures:
Doc & his new best buddy, Rowan who came into our lives back in October. Couldn't not have an Arabian in my life, haha.
Doc is a very special boy and have a fun little backstory on how he came into my life. He was a big lick horse before my friend Nancy bought him back in '03 when he was 8 years old, where she instantly pulled him out of that life, gelded him and gave him a life of love, tons of camping & trail riding adventures. I met Doc & Nancy the same day I met Bear in 2015 when he was being delivered to the boarding barn Nancy was also moving Doc to. Nancy's since retired from riding, and gifted him to me where he's living his life out his life here on my farm where we do plan to get him back out on the trail once all of us are conditioned and ready. He's one of those worth his weight in gold horses. He's had everyone from babies (my niece got up on him with me when she was less than a year old!), to people with special needs on him.