3D modeling and animating are fun to experiment with a create various new things from scratch. Sometimes we can get carried away and not notice certain things while working away. For example, recently I had a project with a provided model that needed some animating. I rigged and animated it in my usual way and it was looking good. Though, once trying to use it in the projects environment, essentially not in Blender's editor, everything went down hill. There were several things that were over looked. The file size way bloated and the animation needed some clipping. This reminded me of my mentors always bickering with me about meeting the requirements before going further with the creative side of things.
The first thing that stood out was the bloated file size. It was four times as large as the environment's limit. I started looking into it immediately even though it kind of stumped me because I had not changed anything about the model at this point. Thinking it was something to do with the excessive amount of polygons that it had I started stripping out the unnecessary polys with little effect. Eventually, on a whim, I checked the file size and resolution of the textures. They were 4k textures and together equaled roughly 95% of total file size. Quickly, I reduced them to 1k each and the total file size was reduced significantly, in fact in was well under the the max limit for the project requirement; roughly half of it. On top of that there was no real change in textures effectiveness or quality.
In conclusion, I wanted to touch on project requirements and how much of a difference each project can with them. Modeling, Texturing, animating, etc... everything that you do for a working project will change depending on the environment that they are used in. For AR, Mobile, or platforms that don't have an excessive amount of resources just can't handle those 4k textures and super dense topology that movies models don't really care about. Both the parties, artist and client, need to know these. If one doesn't problems will occur and it's likely that it will be a delayed finish. Double check the requirements of your project each time you begin working on it. If you don't know them ask or figure them out before you get to far into it.