-- I'm one of those weird people that bought my own saddle to use for my lessons. It's helped me a TON. I got a used Crosby PDN for about $300. It was in great condition and it fit 99% of my trainer's horses, which have ranged from lots of OTTBs to QHs and Appys. It puts me in a good position, the stirrups are always the length I leave them on, and my butt's become accustomed to it.
-- It sounds like you're a little burned out on the mare. If that's the case, you absolutely should try to ride something else for a little while. In the past 18 months that I've been riding again, I've gone back and forth between many, many horses. My trainer moves me on to something new when I've mastered a skillset and need something a little more advanced or I start showing signs that I'm not progressing with my current horse.
I rode this monstrous 17'2 OTTB that was big and beautiful and looked like a warmblood. He was nice and sensitive and not really a typical schoolie. And I loved his trot. But he would spook. At anything. And I'd heard stories about his canter and how he had a pretty big buck when he wasn't in the mood for it. And I rode him purely at walk-trot for 6 long, agonizing months. I never once cantered him. And I beat myself up over it, thinking I was just too chicken. My trainer went out and got a new horse -- I cantered him just my second time riding him.
And now that I've got cantering down again, I'd LOVE to go back and try to canter the big guy I was riding before. I just needed a little confidence boosting from a different horse.
As a student, I've learned different horses help you master different skills. And not every horse fits every student. Also, riding different horses will give you a better perspective all around. Both for your riding, as well as the mare you lease.
Horse owners may feel different, but for me, I've really enjoyed riding different horses and getting to know how they all work and feel and act. Bouncy, spooky, lazy, ****y ... fat, skinny ... horses with lots of suspension, VERY sensitive horses, great, big foxhunter jumps, round hunter jumps, dressage horses, western pleasure horses ...
I think I've rode ... 9 or 10 horses in 18 months.