How often should I change the oil in a stock or tuned 2022+ WRX?

Subaru's recommendation for the FA24 is full synthetic every 6,000 miles or 6 months, whichever comes first, with a shorter interval called for if you drive hard, take short trips, or live in extreme temperatures. Capacity is roughly 4.8 quarts including the filter. For a stock, gently driven VB, follow that and do not overthink it. Modern synthetic oil is genuinely good and the factory interval is not aggressive. For a tuned car, halve it. Around 3,000 miles is the interval most tuned VB owners settle on, and the reasoning is straightforward: a tuned car runs higher cylinder pressure, higher boost, and higher sustained oil temperature. Oil degrades faster under those conditions, and there is no cheaper insurance in the entire modification budget. An oil change costs a fraction of what a bearing does. A few situations that matter more than the mileage number. Short trips are harder on oil than long ones. An engine that never fully reaches operating temperature does not boil off moisture and fuel dilution, and both accumulate. If your commute is fifteen minutes each way, you are in the severe service category regardless of how gently you drive. Track days deserve their own change. A single session generates more heat and shear than weeks of street driving, and the standard advice among people who track cars is to change oil after an event rather than counting it against your normal interval. Ethanol adds a reason to shorten intervals. Flex fuel setups tend toward more fuel dilution of the oil, and a shorter interval addresses it directly. What matters alongside the interval: use a quality full synthetic meeting the specification, replace the filter every time rather than every other time, and check the level regularly rather than trusting it between services. The FA24 is not known for dramatic consumption, but any turbocharged engine can use some oil, and running low is worse than running slightly old oil. If you want to move past guesswork entirely, send a sample for used oil analysis at your normal interval. It tells you what your specific car, driven your specific way, is actually doing to its oil - and it either buys you confidence to extend the interval or gives you a concrete reason to shorten it.