My wife and I are on our 6th Subaru and I have been working on most models 87' and up. In most cases.. most of us may remember that column park light switch being the culprit of battery drains. We have lost that feature a few years back.
However, for years and years 90% of global market subaru's will cut all accessory power when the key is removed. So, battery dying due to something left on other than interior lights, is unlikely. Have you checked that all lights fade out, including trunk? The trunks weigh very little and struts don't always get trunk to close on first try if you're trying to be gentle. When locking remotely, you get one chirp and not four. I have had a cpl bad door switches on new vehicles.
In my experience, batteries are like anything else made and none are perfect, even if branded by the auto manufacturer. For those of you who receive a replacement battery, please ask dealer how they store their batteries. I have worked at some that store them in very cold areas, even on floors (bad!). Even cool floors can kill a battery fairly quickly. I have seen some pull batteries out of cars that have not been run in forever, and cleaned them up and passed them off. I was at a dealership that utilized heavy amounts of silicone, instead of dielectric grease on battery posts to avoid corrosion. This did not prove well for proper conduction.
Not saying this has happened to you.... But my advice is to check manufacturer date stamp on battery case. You don't want to accept anything over 3 months old. If they give you the run around, ask to test battery before install and after and ensure voltage levels are proper.
If you are fearing your vehicle is providing inadequate load to charge your battery, grab a DC voltage monitor at your local auto shop and watch your voltage levels throughout your commutes, starts, warm ups, etc. seems like a bit much, but any insight for the dealer to review may help fix the problem. Check that date stamp.
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