On 31 May 2014 I replaced the battery in my Seiko Coutura, after more than 3 years. I think the battery is only meant to last 18 months. It was still working but I'd rather change the battery early than late. It cost $25 and I think they replaced the o-ring and did a pressure test.
I also sent my Wenger tool in for repair. Initially I was resigned to its terrible quality, then I saw reviews on Amazon didn't mention this, so I thought it wasn't meant to be like that. Anyway, they have a lifetime warranty. Let's see how it compares to Leatherman, and how long it takes.