Any battery charger experts out there?

I bought this cheap one and have been very happy with it. My Ragtop battery is 9 years old and I was going to replace it. I put this charger on it for a week in auto mode and it's been great all summer. Still starting in the cooler temps right now which if it didn't start 1st try last year I'd have to charge it. Now I'm curious how long it will last.
https://www.amazon.com/dp/B0797XMSDL?tag=fabo03-20