Planar drivers generally seem to be a bit less robust than dynamic ones, but it’s mostly a Hifiman problem. They can definitely last long: I’ve got a 40 years old planar (orthodynamic) headphone. Some other companies like Audeze and Monoprice seem to have trouble too (though less than Hifiman), but I’ve very rarely seen people mention a Fostex planar driver breaking (except if it breaks during disassembly).