When you need to prime the fuel pump numerous times by turning the key on and off, that usually is a fuel pressure leakdown problem. Once the car finally starts, does it run smoothly, or does it stumble and run rough for a while?
In general, a car that runs smothly after the prime process has fuel leaking back to the fuel tank, indcating a faulty check valve. This valve is integrated with the fuel pump.
A car that runs roughly after the prime process often hints at a leaky fuel injector. The faulty injector leak residual fuel pressure into a cyclinder, thus creating a flooded start condition (rough).
You might have a leaking fuel line somewhere too.
You can do a fuel pressure test with a store bought fuel pressure tester. A good system will make 43.5 psi when just the fuel pump has been run for 1 minute. (You need to bypass the fuel pump relay to get just the pump to run) It should also hold 2.5 bar (36 psi) after 20 minutes.
This might not explain the no-starts though..... | 
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