See, theres your problem, you're changing it to often.
I change mine about twice a year.
Every 5,000 miles is all you need.

 

That's what I do, every 5k, but I drive about 100 miles a day at min. Rover usually gets a break in the summer, but with moving and house things I haven't gotten to basic stuff the mustang needs so its been parked most the time. Axle bearings don't sound fun right now lol

 

Got it, I didnt know you drove it so much.
I'm only about 12k per year.

 

Lately I've been driving the BMW for saving gas, and my wife's been taking the rover, but it's not much less driving. Once the weather gets bad it's my daily driver again. I think this year will only be 2 changes since it was down a while the beginning of the year for the transfer case, but that's not normal lol.