What happens to a post's payout after the initial 24 hour time limit?

I'm trying to get a better grasp of Steemi's game dynamics. 

I noticed that posts show the payout date. What happens after payout is done? 

For example, an old post has a "Past Payout" of $1 and now it is at $0. If someone upvotes this old post, does the system reset and begin another payout cycle? 

Will an post ever retire and no longer earn any payouts?