Oldest OM-4 do have higher battery drain, but batteries will last much longer if you use silver oxide batteries (357, 303, MS76, KS76, G-13, SR44-W, S76). Alkaline (A76, LR44) and lithium (CR1/3N) have much shorter life. To test OM-4 to see if it has intermediate, lower drain circuit board, turn battery check on. If beep and LED turn off automatically in approx. 30 seconds, circuit is newer style. John