I had these for about two years and wore them daily for at least 3 hours. I would go through a cable every 8 months or so. It would break right where it wraps over the top of my ear. Sennheiser stopped giving me replacements for free after the second. I would recommend you don't get these if you want them to last a long time
Can you provide a little more context behind your usage and care for your pair?
And I am also struggling to find Sennheiser at fault for giving out 2 free cable replacements before getting curious. That's like Ford giving out 2 free sets of tires before getting curious as to what the owner is doing to cord them every 8 months LOL
Not 100% sure but it looks like the "i" stands for apple controls. But the driver on the ie8i looks more similer to the ie80 then the ie8. I only own the ie80 so take this with a grain of sand.