I just changed my 2012 3.5 with 162,000 miles . I couldn't believe how brown it was. I think every 50,000 would be good. I'll wait just a bit and do it again. I've been doing a deep maintenance to get everything synced out. Drvrs side 1/2 axle. Oil. Trans fld. Pwr srng fld. 4 rotors and ceramic pads. Shalom