I was in the PI this past June. I found a bunch of money that I had left over from my last trip in December 2018. All the bills were considered too old and were worth nothing. I didn't see anything that the country was changing the notes, and you had to bring the old ones into a bank to get the newer ones. All in all, at the time it was about US$100. In the US, unless the bill is severely defaced, the bank will accept it as a note that goes out of circulation, and turn it in when they get their money exchanged.