at the age of 13 and up
Alternator is defective or battery has a dead cell.
A raidator in need of a flush will not cause a battery drain.
If the engine is running, then no. The alternator constantly keeps the battery charged.
Highly unlikely.
The wrong spark plug wire(s) can cause engine problems including not running but won't drain the battery.
Computer modules are supposed to "go to sleep" about 15 mins after you shut off the vehicle. If they don't, they can drain the battery. See related links on how to find the bad module. The battery itself may have a dead cell which will cause it to drain overnight. If that is the case the only fix is to replace the battery even if it is a new battery. It may also be you have light that is on pulling power from the battery. Under hood, trunk, glove box, dome light, brake light, etc. You could also have a relay that is sticking.
Yes it can.
A dead cell in the battery will cause it to loose it's charge overnight. The only fix is to replace the battery. Any light that is staying on will drain the battery. Also a stuck relay will drain the battery.
Bad alternator or corroded or loose cables.
Dead cell in the battery. Something on which is drawing power from the battery. Stuck relay.
In addition to acutally driving the car, using the little features such as the lights, horn, radio, and air conditioning/heating will drain the battery of a car. Also a dead cell in the battery will cause it to run down overnight. And if something is on such as a dome light, under hood light, trunk or glove box light. A stuck relay will also run the battery down.
A short in the wiring.