Betta fish lifespan

I was curious as to the avg lifespan of betta fish? Mine recently passed and I had him at least two years. This is realistically my second betta fish, so I’m still learning.
But I’m curious if it was old age.
I have living plants, one ghost shrimp (only one to survive, Sillian, my betta), black sand, and the floating log. I probably could’ve been more consistent with water changes but I don’t think that alone could’ve lead to him passing away.

What improvements can I make for the future?