I used to buy Walkmans from garage sales and fix them up. One just had a belt slip off the spindle. The batteries last a long time. I bought a generic AM FM Cas

I used to buy Walkmans from garage sales and fix them up. One just had a belt slip off the spindle. The batteries last a long time. I bought a generic AM FM Cassette player at K-Mart and it eats batteries fast. How come the Walkman is more battery friendly?