Do you know that? Think of the user and NOT yourself while designing. next

When should a far pointer be used?

Sometimes you can get away with using a small memory model in
 most of a given program. There might be just a few things that don’t fit
 in your small data and code segments. When that happens, you can

use explicit far pointers and function declarations to get at the rest of
 memory. A far function can be outside the 64KB segment most
 functions are shoehorned into for a small-code model. (Often, libraries
 are declared explicitly far, so they’ll work no matter what code model
 the program uses.) A far pointer can refer to information outside the
 64KB data segment. Typically, such pointers are used with farmalloc()
 and such, to manage a heap separate from where all the rest of the
 data lives. If you use a small-data, large-code model, you should
 explicitly make your function pointers far.