A point the authors didn't make is that Common Lisp compilers are quite fast compared to e.g. C++ compilers. So even in rare cases where you do need to recompile everything, the cycle time is short.
CCL's compiler is lightning-fast. I can recompile an entire system in CCL almost as fast as I can load the compiled object code. SBCL's compiler is slower (while often generating faster code because it does more work at compile time), but it's still much faster than a typical C++ compiler.
CCL's compiler is lightning-fast. I can recompile an entire system in CCL almost as fast as I can load the compiled object code. SBCL's compiler is slower (while often generating faster code because it does more work at compile time), but it's still much faster than a typical C++ compiler.