Take the car to a repair shop and have them do an electrical systems test. It should include testing the starter for the amount of current dtraw it has. Also the alternator for amperage and voltage output and the state of the alternator. If the battery is low then you will get a bad starter reading.
You know the starter is going bad when you have a dragging starter.
Remove the starter and have it bench tested.
Remove starter and bench test it for operation and current draw
You need to remove the starter and look at the teeth on both parts.
Remove the battery and take it to an auto parts store for testing. They can tell you if it is bad. If it is good, then remove the starter and do the same thing.
If the starter does not turn then it could either be bad or not getting power. If a volt meter can not be used to determine that voltage is present, then the starter can be pulled and taken to be tested.
Remove it and have it bench tested.
jump the starter solnoid, if it will crank , turn key on and jump again, if it starts then key switch is ok it would be the starter solnoid that's bad,
If a starter relay or solenoid is bad, usually you will only hear a single click when you turn the key to start the engine.
Remove the starter and inspect the ring gear on the flywheel.
Good power all the way to the starter, 12 volts at solenoid/start circuit wire when key engaged, but no click or starter engage
First, turn on the headlights. Now, have someone watch them as you try to start the car; do they get dim? If so, the battery is in need of a charge; If not, you need to check your connections at the starter. You may have a bad starter, starter solenoid, or connection.