Style Recommendations (CMUCL User’s Manual)

Source level optimization makes possible a clearer and more relaxed programming style:

Don’t use macros purely to avoid function call. If you want an inline function, write it as a function and declare it inline. It’s clearer, less error-prone, and works just as well.
Don’t write macros that try to “optimize” their expansion in trivial ways such as avoiding binding variables for simple expressions. The compiler does these optimizations too, and is less likely to make a mistake.
Make use of local functions (i.e., labels or flet) and tail-recursion in places where it is clearer. Local function call is faster than full call.
Avoid setting local variables when possible. Binding a new let variable is at least as efficient as setting an existing variable, and is easier to understand, both for the compiler and the programmer.
Instead of writing similar code over and over again so that it can be hand customized for each use, define a macro or inline function, and let the compiler do the work.