1. How to avoid some common pitfalls
Unexpected grid cell sizes
TauDEM crashes

2. Project Raster
Also Project Streams using Vector project function

3. DEM Reconditioning
Can result in cell sizes for the AgreeDEM that differ from the original DEM. I presume (guess) that this is due to the system retaining some geoprocessing setting information from the projection operations. To reset, close and reopen ArcMap.

4. To Avoid: Save as …, Close and Reopen the ArcMap Document

5. Avoid Spaces in TauDEM file paths and Names
TauDEM will Crash!

6. Move work to a location where the path has no spaces