When is a first UOA viable? I see some people do it when the engine is quite new. However engines break in and I imagine influence the UOA's and it seems to state that in reports. Really my plan is to do a few to see if a 7500 OCI with Mobil 1 in 2004 WRX is viable or just stick to safe 5000 oci with Mobil 1. The 5k is fine but $$$ since I don't want to change the oil myself for warranty purposes and my trusted mechanic charges $54 for Mobil 1. I just don't trust Wally World although they only charge $27 for Mobil 1/SuperTech filter.