Hmmm. Topo maps are an interesting subject- at least, to me. The current LINZ maps of Rotorua (where I live) are based on aerial photos taken in 1975 and produced on an electro-mechanical plotter in 1977. The plotter made analogue maps- not digital! on draughting film. The projection was based on a now-obsolete mathematical construct of the world.
Since then, the analogue pictures have been digitised, adjusted to a new projection, and periodically 'updated' by a contractor, working within a budget. I am sure that the contractors compare the 'old map' with new aerial photos (or even satellite photos!), and alter things like vegetation cover, land usage, housing, roads, etc. I expect that they also use GIS data from local bodies to help them. But the basic map was made some 40 years ago.
The 'bones' of landscape do not change fast (except say in Christchurch lately). I think that it is a great tribute to Lands and Survey all those years ago that they did such an enduring job! But it must be about time that the topo maps were replaced with new from the base up.
And, a personal thing of mine, that private roads (eg permanent forestry roads) were named.