With the advent of the Models.cached and Units.cached, I can't count the number of times I was puzzled when a new or changed Model/Unit didn't seem to be effective.
These files are created when you first load the game, but only if there is no version of the files existing!
The caches do significantly reduce game load time, especially in newer games with voluminous models and units (RoP,RED, VGN), so I don't recommend leaving these "on" for routine play (I use JSGME to swap the file in/out)
To help your modding/dev work, simply put the attached file in \Settings folder of your game, delete the two cache files, and viola , the caches will not be created!
I've confirmed that this works in WIA 1.08 rc6, and AACW 1.16 beta 7.
(It allows testing of AACW beta 7 while we await the Master's fix of the "cache crash" bug :w00t