I've have a gallon of Franklin TiteBond II wood glue I bought back in
1995 --back when I had more ambitious plans for further woodworking projects. It's been sitting in a variety of environments, including sub zero winter temps. I thought I could find an expiration date on the jug but I can't see it now. The color now is between orange and "school bus" yellow. It smells vinegary. I went and bought new little bottle at Lowes yesterday, but I wanted to see how the old stuff performed before I throw it out.I took two pieces of scrap yellow pine, spread a circular dab on one of the flat faces (not on the end grain), mashed the pieces together, did not clamp, and left it to cure for about 20 hours.
This morning I clamped one end in a vise and tried to knock the other off with a hammer. It took some effort, they did separate, but the glue was still obviously stronger than the underlying wood. Big slivers of wood from one piece still stuck to the other within the dab circle. With a fingernail the hardness of the glue was about the same in my experience as if I used fresh glue. I just wanted to make sure it wasn't brittle.
The major disadvantage is application. It is way more viscous now. It would never squeeze out of the bottle thru the applicator tip. I had to unscrew the cap and squeeze some out thru the bottle end. The consistency is close to say refrigerated hot fudge sauce, slightly pasty and a tiny bit elastic. It is best spread with a putty knife.
I guess I'm not going to throw it out after all, since I eschew waste, but I probably wouldn't use it for a primo project.
--zeb