Bruce Willis revealed https://movieweb.com/bruce-willis-says-die-hard-5-is-coming-in-2011/earlier this month that he will begin shooting Die Hard 5 in early 2011. Now, he has stated that he will also be back for Die Hard 6. But after that, he will officially retire from the character and pass the baton onto another willing actor.
"In the next few years they could easily find a replacement for me or call the character someone else. But for me, I want to do Die Hard 5, then one final Die Hard movie - Die Hard 6 - before finally hanging that white vest up for good. At the moment, I can run and I can fight on screen. But there will come a time when I no longer want to do that. That's when I'll step away from the Die Hard films."