One thing I've considered too as I begin to work with more and more developers on larger projects is the good ole 'Bus Factor [0]. In short, it's determining whether or not your project can be sustained should the major contributor or 'main brain' behind the project get hit by a bus. The entire objective is to reduce the number of places the project can fail, simply by having one member pass unexpectedly. Should you steer clear of avoiding a single point of failure? Absolutely. Is it always avoidable? Absolutely not.

[0] - https://en.wikipedia.org/wiki/Bus_factor