Regression testing is often performed with a time budget and it does not allow executing all test cases. Test case prioritization techniques re-order test cases to increase the rate of fault detection. Several time-aware test case prioritization techniques have been proposed to satisfy a time budget. Since it is difficult to collect the time cost of each test case in some cases, a natural question is whether it is worth using such information when prioritizing test cases. In this paper, two most popular criteria: statement coverage and fault detection are considered for time-aware test case prioritization. We investigate whether the time cost of each test case affects the effectiveness of prioritization techniques, i.e. the rate of statement coverage and the rate of fault detection. Our empirical study shows that: although the techniques considering the time cost of each test case are slightly better than the techniques not considering such information in some cases, they have no si...