I have no idea, and that's just fine by me.
This is a Toyota, so there's no specific mileage or age to trade in.
Not having a warranty is of little concern.

I sold my last IS300 after having it for 11.5 years. I had no real good reason to sell it, as it was in a great shape. I figured it could last another 10 years, then added it to my age and decided to try something new.

 

My 2002 hit about 110,000 before I sold it. Suspension definitely was worse towards the end, but still more comfortable than a pickup (shocks/struts never changed). Still drove like a champ. The main thing I noticed is in the winter. The car doesn't shift out of 2nd gear (maybe 3rd - don't quite remember) until it warms up. Apparently this is a Lexus thing where they specifically don't change gears, but i never noticed it until the car was around 90K-95K miles. Maybe the car just took forever to warm up at that age...don't know. To answer your question, I'd say consider trading it right before 100,000 miles. Just keep regular maintenance and make sure and do whatever the maintenance book tells you to do along the way. Sure they'll last longer, but you'll be ready for a new car before you hit 150K-200K.

 

I've had mine since Nov 2009, and it is currently sitting at 135k miles.

I've done all regular maintenance; done a brake job both front and back; I'm on my third set of tires.

The liftgate isn't extending all the way up now without some pushing, and the steering wheel has just recently added a new crunchy feel that needs to be checked out (I was one of the first to report the steering wheel "groaning", and the dealer never found anything wrong).

Other than that, it's been solid.

 

I have read the threads on how long to keep your RX, I have a 04 RX330 which now has 129000 miles on it. All service was done as recommended and I change oil every 3k. Still using 5w 30 and no oil burn and no problems. I plan to keep RX until 250k miles and repair anything that needs to be repaired rather than spend on new car that will last longer than I will. I am 73 and this RX runs better than I do. Still looks great and clean and tight. Only problem with it is a little white smoke once in a while when I park on incline and first start it up in the morning. I was told it was valve seal which makes sense. Not worth repairing yet. Lexus also just replaced my dash top under warranty which speaks well of Lexus. I also have a 1997 Lexus ES300 with 104000 miles on it that is in the same great condition. By the way, my past 11 cars were Jeep Grand Cherokees before buying the RX. Miss the Jeeps but glad I have the RX

 

I have 252k on my 2001 RX. It won't die. I have a couple of small issues nothing crazy.

 

Change the fluids when it calls for and 200,000 minimum.

 

My now retired Dentist had a 2004 RX that had 260,000 miles on it. Original engine and transmission. I sold the car for him about 3 years ago and it ran great. I just had to replace a noisy Left front wheel bearing before I sold it for him. I worked at United Parcel Service from 1976 to 2006. The routinely keep UPS delivery vehicles up to 25 years. These trucks get hammered every day. Where I worked, we had long range routes that they used Ford Econoline vans on. The engines routinely went 300,000 and one went 424,000 miles before it broke a piston. The engines were 300ci 6 cylinder engines. The vans lasted about 600,000 miles before the bodies got kind of loose. Routine service, the right kind of driving and knowing the vehicles limits are key to longevity. I drove 28 foot International box trucks that had 550,000 miles on them with the original engines and I felt confident in them.

 

I have a 04 RX330 AWD with 134000 on it. Change oil every 3000 miles and regular tune ups and belt change. I also flush and refill tranny and rear end every 30,000. Everything works just as it should and I am planning to keep it until 200,000 miles. I also tow a 1200# boat and trailer now and then. My only problem has been that I bought the car with 80,000 miles on it and didn't know what the past owner had done. Every once in a while I get a puff of smoke at startup when cold. My mechanic tells me it's a valve guide seal and not to worry. Seems to happen a lot with that engine.

 

Just sold my 2004 RX with 303,000 miles. The problem isn't the mileage, it's that small things pop up more frequently, and the wife didn't like that. I could have spent around $2,000 and been good for another 100,000 miles. It drove like a dream!