1997 Dodge Caravan continually need to jump start car

Had it in garage. They put new cable ends on battery cables, cleaned terminals, etc. All ok for 3 days. Then click, click again. Jumper it and it starts up instantly. Back to the shop. They changed out one of the new cable ends again, checked everything out and returned veh. Ok for 3 days, then same problem. Last time it wouldn't start, the mechanic said he was going to check the alternator. I assume he did.