Hello all. I am going to be submitting a used oil analysis(UOA) to Blackstone Labs when I change the oil. I've never had a UOA done before so I am curious as to the results, and I will be paying the extra $10 for a TBN. I use Mobil 1 5W-30 and AC Delco PF48 oil filters only. I usually change the oil and filter every 6K. I suspect I am changing the oil too early, but the TBN should be able to answer that. On to my purpose for posting the thread, I normally change the oil and filter every 6K, should I change the oil filter at the halfway point? Walmart sells the PF48 oil filters in my area for $4 each so it is low cost. Thanks.