Help, growing from two to three

I have run a two man development company for the past 2 years. Its had its up's and downs but overal its been great.

Over the last 6 months our money has been nearly the same each month.

We have tried to take on more work and manage the projects between us but that lead to missed deadlines and broken promises... Not our style.

Is it worth taking the risk and employing someone who we can just about afford, hoping we can take on more work?

Or is it better to save and keep money in the bank for a bad month?