I am still using my free ones up that i received with new purchase but the same dealership does my Lexus and they only charge me like $16 for labor and their filter for the oil change if I bring my own oil. Not sure what the filter actually costs for the Lexus but it is a canister drop in and I think $16 is more than fair for labor, filter and topping off other fluids like brake, windshield washer, etc.
Reason I worry about interval is as stated in previous post, should on the off chance I sell the vehicle or was ever denied the guarantee for some crazy reason I want my vehicle in top shape period as far as quality, performance, and mpg. Just a personal thing.
For $16 bucks I'd have the dealer do it too, and if it includes the rotation it's bordering on theft. Except for one of my earlier threads and what they did to my oil filter drain valve. And the fact that I have never seen a Toyota dealer here do what they said on the checklist - they'll rotate a tire with 15 psi in it, call it good, and impact wrench the lock nut on there good and extra tight for you. And boy do they get huffy when you point it out. Lifetime warranty or not, having the oil filter canister crack, or discover they broke your lock nut tool, miles from a paved road isn't my idea of a good time.
You're right on the 3rd party warranty though, they'll find some way to get out of it if they can.
As far as selling the vehicle goes, past a certain age nobody seems to care how well the thing was maintained. Or how poorly. You might, I might, but the public at large has zero concern. In the DC area there are still people asking $7k plus for a 1998 Tacoma with blown axle seals and a grinding clutch. And apparently, there are suckers paying that.
We can agree to disagree on the interval, but heck, if it's that cheap, you might as well. Given how far south you are, you can run 5W20, that's cleared for 5000 mile intervals per your manual. You can save a buck, or at least shop around, since good 5W20 synthetics are much more common. Also, sometimes you can score Toyota 0W20 for 15% less than Mobil 1 - call around the parts departments for a case price. Honda/Acura also sell 0W20 that meets the specs for less that Mobil 1 once in a while. All have tested well in the lab, although apparently Toyota's formulation has the best cold flow properties down to -20, after which Mobil 1 is better. (this is per bobistheoilguy.com, where people actually post lab results).