I'm aware than unsigned int and size_t are usually equivalent, although size_t is less... operating system dependent for some reason. I'm also aware that in some places, if you use either int or size_t, you convert type instead of compare.
I'm not really sure WHERE I need to use one or the other. I'm primarily asking this because when messing around with some virtual machine code I found on gamedev, it used size_ts. Converting them all to int did not affect the code.