... old Jeep burns 6 qts in 3000 miles anyway.
Likewise my ‘90, 195,000 mile Taurus SHO. I just keep dumping decent oil into it and change the filter every once in a while. Wife and daughters have better vehicles, of course, and they get syn oil & filter every even 10K.
Unless the addition of a new 6 qts to the dregs retains the last 3000 miles accumulation of metal bits and corrosive oils. In that case, it might be beneficial to remove even the last quart, otherwise it will accelerate wear-n-tear.
You still need to change the filter every once in a while.
I’ve heard that before, but remember that it is only burning the light stuff. The sludge is still sitting at the bottom; thus contaminating the light stuff.
LOL! Mine's not quite that bad, maybe 4 qts. But it's an old honda with 196,000 miles so I don't much care anymore.........It's better than a car payment.