Does anyone have any direct experience with plastic boxes not aging well?

Brittleness?

I'm rewiring portions of a 1930's cape cod, which is all metal box, and wondering if 50 years from now the plastic boxes I'm using will be in as good a shape as the metal boxes I'm finding. In theory, probably not, but I'm wondering if anyone has encountered plastic boxes that have 'aged out'.

Definitely seem to get less pliable with age. I wonder if the salty air of the Cape is worse for metal boxes or plastic.

I don't think this answers the question at all, but I have heard that all the plastic products that we bury in landfills will still be there hundreds of years from now.

I have a lot of faith in the durability of plastic. After all, if it is good enough for water and gas mains, then it is good enough for electrical boxes, IMO.

Peter

plastic is pretty durable as long as it is not exposed to UV light, unless it is UV resistant. also, heat can dry out the plastic. if the plastic is in the dark and not often exposed to temps over 90 degrees, it should last practically forever. if the boxes are installed in an attic, i would expect to see some deterioration in 20 years or so, but i don't think it would be a safety hazard. i don't think the boxes will ever just fall appart by themselves.