I got the Alternator replaced 3 months ago. Now, it broke again.
What are the warranty terms.

The alternator itself is covered. But what about labor?
The make is Denso remanufactured.

Any way to monitor Alternator before it fails?

It is sad that re-manufactured alternators are notorious for failing in a relatively short amount of time. There is rarely any warning that an alternator is going to fail. You could get a voltmeter and monitor the output voltage of the alternator, but many times the failures are caused by an electronic component (such as a transistor) going bad and that is like a light bulb, it works and then - poof - it's burned out..

The only place that can answer your question about the labor to replace the alternator again is the place that did the original replacement. My experience has been that you will have to pay again. It seems like places only give you a 30 day warranty.

But don't go by what I say, call the shop and get accurate information.

My alternator had a lifetime warranty from Pep Boys and recently died. The alternator was covered under warranty and I had to pay for labor.

I am gonna end up getting the same Delco alternator. No other choice now.

Can I go to a different mechanic and get the alternator replaced under warranty?
All I have is the Bill the mechanic gave me from the 1st replacement.
No separate receipt for the alternator.

How much was the labor cost if you don't mind.

You need to have the actual receipt for the purchase of the alternator from an auto parts store or supplier in order to get a warranty replacement. Without that, you or another mechanic cannot get a warranty replacement.

Took the battery to Autozone to get it recharged so I could drive to the Mechanic. They did a one hour charge. Voltage was just 12V. Was 11V before. They did a diagnostic on the battery. It came out as bad battery. This battery is less than a year old

Update: Borrowed by neighbors battery and went to the shop. When I put in the battery, all the ABS/Brake lights were off.

The mech replaced the battery and did a battery check using a gizmo. The test passed. The alternator voltage was 13.33V. The battery was Interstate MT35, just one year old.
When I tried to get my battery recharded at Autozone. They kept telling me its bad and the voltage was 11V. I thought they didn't charge it. But turns out they were right.

Phew! I just saved a bunch of money this weekend.

Question: What lights on dash board turn ON when the battery is low or dead.