IMO about 30-60 years.
Hard to say how the current releases will hold up, but I have no reason to believe they’d fall apart anytime soon.
And just to give some reference:
PdB vertical 2016-1970
PdB Riservas, pt. 1: 1978-1961
PdB Riservas, pt. 2: 1988-1982
PdB Riservas, pt. 3: 2004-1989