What is the difference between nbn's New Development and Co-Development programs?

The New Development program is for new property developments requesting for the nbn™ network installation at the premises. The Co-Development program only relates to the early installation of conduits and pits in locations that support  nbn's rollout. 

In some circumstances, access roads to a new property development may provide an opportunity for co-development and developers are encouraged to register their access road infrastructure projects with the Co-Development program.