I just wanted to reiterate what's probably been said a million times before on here, but make sure you track any and all maintenance on your car.
I'm at 53,000 miles, bought the car used with around 36,000. I've changed the oil 4 times on the car in the 14 months I've had it. On my commute home just before the holidays, I started hearing it knock and the dealership confirmed it's an engine problem. I suspect I'm hitting a spun rod bearing like a few others on here (sounds just like some youtube videos) however they asked for maintenance records. The best I can provide is a facebook picture I took when I did my first oil change and my most recent receipt because I decided to start buying from Amazon. Unfortunately O'Reilly wasn't able to pull up my purchases so at best I can prove two oil changes 10 months apart.
Currently I'm at the mercy of Subaru corporate to authorize the warranty work
Keep records! From now on I'm keeping a box in my garage with all receipts and will make note of mileage.