There's the classic joke about "if I was going to X I wouldn't start from here".

I took a job once, where the employer's prime motivation was to bring talent aboard to launch a long-overdue rewrite of a business-critical app. The question I failed to ask was, why have you ended up in this situation in the first place? It should have been a red flag, whether the cause was too much pressure to add functionality to maintain and incrementally refactor the beast, too little ability in the department, too little buy-in from clients or management for incremental work, or whatever, and this cause festering away until the problem reached an intolerable level. So I'm going to agree with Joel in that a massive rewrite is probably a very bad idea - unless you have firm evidence that all the underlying reasons behind why a major rewrite seems so necessary have been dealt with, you're in all likelihood going to repeat the problem in due course.

There's the classic joke about "if I was going to X I wouldn't start from here".

I took a job once, where the employer's prime motivation was to bring talent aboard to launch a long-overdue rewrite of a business-critical app. The question I failed to ask was, why have you ended up in this situation in the first place? It should have been a red flag, whether the cause was

• too much pressure to add functionality to maintain and incrementally refactor the beast,

• too little ability in the department,

• too little buy-in from clients or management for incremental work,

or whatever, and this cause festering away until the problem reached an intolerable level. 

So I'm going to agree with Joel in that a massive rewrite is probably a very bad idea - unless you have firm evidence that all the underlying reasons behind why a major rewrite seems so necessary have been dealt with, you're in all likelihood going to repeat the problem in due course.