There are two cases where the tiling the renderer chooses may not be optimal.
Over an animation texture, chattering can occur because the tiling configuration changes. This does not happen very frequently but if you have a noise-based texture on an object that is not moving and you have another object (highly tessellated) that is moving you can sometimes see texture crawl because of tiling changes. The way to check if forcing tile sizes will alleviate the problem is to observe if over the animation the texture shift is occurring in a rectangular region (aligned to tile boundaries).
Sometimes the memory estimation is wrong and your rendering job can't finish. If you see something like:
Error: Free memory is low. Memory exception thrown
You can try to force the tile sizes to be smaller so the rendering job fits into memory. When using command line rendering, use the -reg <int int int int> flag. For more information on this flag, see Common flags for the command line renderer in the Rendering Utilities guide.
