I generally do all my own maintenance, except routine maintenance while under warranty. Reason being that warranty issues are going to be easier to deal with if you have required service history at a dealership. I know this isn't required for warranty, just makes it easier. But I will do things like bring my own oil. When I had to have the front cover leak addressed on my GX and when the evap canister died on my wife's RX450h having service history at the dealership made both of these no questions asked repairs (especially as my wife's was out of warranty on time but very low miles for age; this was a >$1000k repair that Lexus went ahead and warranty repaired).