True or False When choosing the sample size for estimating a

True or False? When choosing the sample size for estimating a population proportion p to within E units with confidence (1-a)100%; if you take p=0.5 as the approximation to p, you will always obtain a sample size that is at least as large as required.

True, this is what we do if we do not have a prior estimate, because p=0.5 gives highest standard error possible (Worse case scenerio)