I am a strong believer that adding more people to your already late software project is a guaranteed way of making the delivery of it even later.
First it takes the new people time to get up to speed and figure out what needs to be done, but more importantly, how it needs to be done.
And secondly, the more people you have on a software project the harder you have to work as the project manager to divide up the tasks so that that they can be done in parallel.
Also, I need to let my boss know we’re behind schedule and need to hire more people.