on older(like 5-6yrs old, which I COMMONLY shoot(cuz it's cheap !) film, I test a roll doing the following(all of the same scene, camera on a tripod, I'm not creating art here ):
shoot a grey card in 1-2 frames
meter how you usually do(spot, ambient, etc., whichever way you regularly(and reliably) work, in general)
if you have a warming filter(81A, or a skylight(not really warming since it's mostly pinkish, but helps at higher altitudes) use that on a few frames as well
rate 1,2, and 3 stops slower than box speed(so 200,100, 50 for 400ASA(box speed) film)
My general guess is that you'll have a slower ASA by approx 1-2 stops, and some color shift towards blue/magenta. This is based on my shooting of a few purchased quantities of older(pre-2000 dated, but cold stored nonetheless) Fuji(especially) emulsions. Kodak and Agfa usually went somewhat blue, Agfa sometimes went a bit warmer(which I liked personally).
Have fun, make sure to test though prior to committing time and energy to shooting stock that might just be good to grace the trash can's presence, and not your camera