I'm going to have to replace some sections of roof sheathing
as part of a re-roof project. What is there now is 1/2" plywood.
I guess it's been OK because it's lasted almost 30 years.
Is 1/2" still OK as far as code goes, etc?
The part that is a problem was due to not being vented correctly,
which I'm going to fix. It's actually one entire section of roof
where that whole section needs to be replaced.

I'm going to get quotes and want to make sure everything is
spec'd. What is typically used now for roof sheathing? Is OSB
ok? is at as good or better than plywood? Oddly looking at Lowes
and HD, it doesn't look like they have sheathing in 1/2". Closest is
15/32.
I guess maybe lumber yards have true 1/2"?