Home Depot wire?

I know a lot of industrial applications use one color only, but yes it is labeled. I not sure what gauge I would need, I’m sure thickness of insulation and age of it is different from new ones. I was thinking when in doubt go bigger so less resistance, am I wrong? Color coded would be nice, but I don’t think I can find all correct colors anyway, but if I do one at the time as needed it should be ok. Of course later trouble shooting will be fun , a lot of ohming out ...