Needed some PCB material with the photo resist coating - the sort you use for making your own. I ran out a couple of months ago - and that 'stock' was several years old, just stored indoors in a drawer. The new stuff came from CPC - after Maplin, who are cheaper for apparently the same stuff - f***ked up by taking ages to deliver - then sending the wrong bits. CPC delivered this morning after ordering yesterday.
But what I noted on the CPC blurb is the shelf life is only 6 months when stored between 10-20C. Are they just being conservative? As I said the last stuff worked perfectly after more than that in years.