Digital BW, The Print

This may be a basic question but I recently acquired a pH testing pen
and have been using it on various papers I have.  My main papers,
Harmon FB Al and Innova Smooth Cotton 315 both appear to be
non-acidic.  However the Epson papers I use both look to be quite
acidic.  

I am wondering how time will affect these papers.  The tests over at
Aardenburg of pigment inks on Epson Premium Luster do not indicate
much change in the paper as a result of decades-equivalent UV exposure
(loss of UV brighteners but that's about it).  

What I'm wondering is how will the acids in the paper ultimately
affect the print?  How concerned should I be with works I've printed
on Epson semi-gloss or Premium Luster and stored in a dark album or
behind glass?