Ninite Pro automatically saves and reuses downloads in a NiniteDownloads folder it creates in the same directory as the Ninite .exe. Ninite Pro still checks for new versions of applications and downloads them if they are not already in the cache.
To specify a different cache location, like a network share, use the /cachepath switch:
NinitePro.exe /cachepath "<your cache path goes here>"
Use of the cache can be disabled with the /nocache switch.
We also have an example of placing the cache on a network share.