For those risk analysts out there using Monte Carlo in their analysis, have you ever wondered why the industry standard for simulation sample sizes in Monte Carlo is set at five thousand iterations?

So many Monte Carlo systems I see in use today run a standard five thousand simulations but why five thousand, why not ten thousand, why not five thousand and one?

How many samples should we have in our simulation sample size and when is the number of iterations insignificant? To be concise, if you were to add another sample to your Monte Carlo simulation, when doesn't it make a difference to the final result?