Camshaft position sensor

I see alot of replacement being completed for these two sensors. I am currently researching for the possible next steps, once I completed with the fuel system.

My question is, why is everyone replacing the distributor when I see that Autozone carries a replacement for the camshaft position sensor (otherwise known as the sync signal generator) ?

Thanks for the help.
Chris

Sorry ... the crankshaft sensor is the second I refer to.