What does it take to be an independant project manager?

Mahalmadane -

1. A wide network of advocates who can help you land your next gig
2. Sufficient depth and breadth of experience to be able to tailor your approach to the culture of a new client and the context of a new project
3. Discipline to continue to invest in your personal development without a company paying for it
4. Financial reserves to see you through lean times

Kiron

At least you can afford to survive six months with out a single dollar income

Everyone's situation will differ but the most common denominator for everyone that is all encompassing is know your risk tolerance and plan accordingly, we are afterall project managers we should walk the talk.

Followed by:
1. cover your bases/contingency planning(i.e. financial reserves, live below your means)
2. pipeline of opportunities readiness,
3. metrics, metrics metrics - know your best/worst case range of magnitude with course of action ready,
4. don't put your eggs in one basket, nothing is 'permanent' or guaranteed.

On the softer side:
stay positive, be persistent and have an entrepreneurial spirit with creativity and resourcefulness.