M indirection provides a very powerful tool for allowing program abstraction. However, because indirection is frequently unnecessary and has some disadvantages, use it carefully.

Because routines that use indirection in some ways do not contain adequate information for easy reading, such routines tend to be more difficult to debug and maintain.

To improve run-time performance, GT.M tends to move work from run-time to compile-time. Indirection forces compiler actions to occur at run-time, which minimizes the benefits of compilation.

M allows most forms of indirection to be recursive. However, in real applications, recursive indirection typically makes the code obscure and slow.

There are circumstances where indirection serves a worthwhile purpose. For instance, certain utility functions with a general nature may be clearly abstracted and coded using indirection. Because M has no "CASE" command, DO (or GOTO) with argument indirection provides a clear solution to the problem of providing complex branching.

Some M users prototype with indirection and then replace indirection with generated code that reduces run-time overhead. In any case, always consider whether indirection can be replaced with a clearer or more efficient approach.