All depends on driving style. More go pedal, the more def is used. I did a snowmobile trip to Canada this winter, 4000 lb trailer, and it was 1200 miles round trip. Had to refill in Canada.I’m at 4600mi with my 19’ Lariat and I’m almost empty on DEF. Is this normal? I read somewhere is was supposed to last till rough 10k. Anyone else have similar issue.