I've had my Mazda 3 2013 since 2016. This winter in Massachusetts it's died on an almost daily basis in the morning, and sometimes at night if it's particularly cold out.
I mostly drive to school, work, and to a friend's house, each commute only taking about 30, 8, and 10 minutes respectively for distances at most 12 miles. So I'm aware that I drive short distances and use a lot of amperage to get it started in the cold.
How do I know whether or not I need to completely replace the battery or just give it a good charge? I have an external jump starter (one of those small battery packs) and I typically only need to leave it connected for 30 seconds-2 minutes before I can jump start my car. The battery indicator in the dash is also not lit, and my leads don't have corrosion.