I know this is an old thread, so ridicule me if you must (though I won't be viewing replies, so ha).
If you want pad-printed legends to last, wash your hands before you sit down to type. Dirt is abrasive. I'm convinced that's what causes most of the wear on PP legends.
Of course some people have acidic skin, so this may not help them. But I've owned many PP boards, and I type a lot—and typing with clean hands, I've never seen any wear, ever.