Any idea when someone should replace the thermostat

Any idea when? I have changed the radiator fluid about 2 times in 10 years . 137000 miles

 

Toyotas rarely have thermostat failures.

They typically failed in the old days because the coolant became corrosive sooner and would eat everything.

A sign you need a thermostat is it doesn't reach operating temperature, or constant overheating.

It's not a maintenance item, you repair them as needed. Because you're on top of the coolant flushes, you'll be fine.

The new 2016 + models are failing due to the electronics in the thermostat, so be glad you don't have that concern.

 

Thanks for the info . What about the hoses ?

 

Those will last you quite a while. Joust look for cracking and dry rot every now and then

 

There is no set life span on radiator hoses. In general the automotive industry suggests replacing about every 60,000 miles or every 5 to 6 years. The responses to your question are going to be all over the map. I replaced mine at 90,000 miles. So I’d say replace between 60,000 and 100,000 miles or 6 to 10 years.
In any event you don’t want to wait until they fail. They are cheap so just look at it as being normal maintenance and replace them sooner than later.
You’re going to have guys saying they have a zillion miles on them and they are fine. But it makes no sense to wait until they fail because again they are cheap. So somewhere between 50,000 and 100,000 miles , what ever you feel comfortable with just replace them.
If you have 137,000 miles on the hoses just change the damn things.

 

The ecu will throw a code if it starts failing, thats when you need to change it.

 

I replaced my belt, PCV, hoses and thermostat when I did my first coolant flush, at 100K. They looked in very good condition. I now recommend to do them at the second flush, at 150K, unless there is observable damage. Im not going to wait for them to fail.

 

The usually fail full cooling so it’s not a big deal. I view it as a run to maintenance item and not replace on a predetermined interval.