In the US, it is fairly dependent on which state, how old the signage is, and who owns the road. On Federal Highways, I haven't seen button-copy (The small reflective buttons on letters & such) installed in a very long time. Sometimes highways will get signage updates to many signs but others will be reinstalled on new posts, so you might see button copy around longer in those cases.

When I drive through California, however, I see lots of older style signage or posts that is phased out most everywhere else. I suspect due to budget constraints.

The retro-reflective sheeting is WAY more popular and effective, but it's also very delicate and easy to scratch. I also think it only has a 10 year lifespan (technically at least. In practice states seem to keep it a bit longer than that since it's so expensive)