I’m glad the imagery is working for you. I too am a huge fan of “If it ain’t broke, don’t fix it”, so I don’t see any reason to change it. If you haven’t gotten tired of listening to it after a year, you may never get sick of it.
On the other hand, I, like you, am also a subscriber to the “change your shampoo now and then” approach. So it might not hurt to introduce yourself to a new CD, just for variety…. but there’s no need to worry about growing immunity to the CD. You won’t.
You might get tired of it - but if you listen to something new and then go back to it, it will sound fresh to you again. And even if you kept listening to it while being sick of it, you’d still benefit from it. We learned this from a weight loss support group that was being followed by 20/20. The deal was, they had to listen to the imagery every day for 6 months, until the camera crew came back to tape the follow-up. Most of them had had it with that imagery by then, but they were good sports and kept listening to honor the agreement. In spite of being tired of it, they continued to lose weight.
So either way is fine, Danielle. If you keep doing the same thing, that’s fine. If you eventually add to your library, that’s fine too. You can always go back to this one.