Very fucked O rings there Rick. I would suggest the 4 years was not the issue but lack of lube. Looks to me like they are torn apart rather than worn out. Lube it up man!
JD
The manifold in question was one of two sets I am servicing at the moment.
The first manifold I did was in much better condition than the one shown, even though it had previously been serviced about the same time.
Both sets had been done through a dive shop.
The residual lube in the bad set had dried up, backing your comments.
Will be lubing strongly :-)
Cheers