Joel's assertion applies to the situation where the old code and the new code will reach roughly the same complexity at the end (for example, this is often the

Joel's assertion applies to the situation where the old code and the new code will reach roughly the same complexity at the end (for example, this is often the case when the requirements are complex enough and cannot be changed). If you have a very good idea to greatly reduce the complexity, ignore him and go ahead. In the other words, the point is that you always have to do the cost-benefit analysis for any such endeavor and the history tells that rewriting is intrinsically very expensive.