my experience has been they can fail anytime after 10 years the plastic gets brittle from being subjected to hot/cold over and over. if yours are the original 13 year old one's I would replace them. I now replace mine at 5 years just for good measure, because when those blow out (at any time) you generally do not know it has happened unless you are stopped and see steam. moving they just blow all the coolant out and you overheat and if you are not paying attention you do not even know until it either looses power or you get reduced engine warning and by then you have already overheated and you don't get too many chances when overheating a engine once or twice and you most likely fine but more than that and you are risking serious engine damage.
and if they do not flat out break off then they will just slowly leak coolant out until you end up in the same position as above unless you are studious about checking under the hood or notice a puddle in the garage or driveway.
I had a very slow leak from them on my 2005. I did them about 1 year ago. Do them now if you have never replaced before. They will "give up the ghost" but never in your driveway. Although, I must say, I found mine leaking in my driveway.
In addition to the T's, replace the two heater hoses that go between the T's and the water pump. The plastic fittings on the ends of the heater hoses also get brittle and fail just as easily as the plastic in the T's.
I agree with the comments above. At your mileage, you should replace the Tees and ALL cooling hoses in the engine well. You can see the manufacture date stamped on the hoses, and I'll bet that yours are the original hoses. For Tees, use only OEM plastic Tees (no Dorman Tees), or use metal Tees made by Gruven.
I can tell you from personal experience that losing a Tee or the heater hose that connected to the Tee will empty your motor of coolant within 60 seconds.
Last, when you replace the Tee, use gloves, as the insulation on the fire wall is quite aggressive, or your hands will be itching for a few days.
My 07 went at about 195,000, in eastern MT pulling a boat to Fort Peck. It was a real PIA situation. Luckily, I carry a tool box on trips like that and had some radiator clamps and water. Gerry rigged it, to get to the next town. No parts available so had to improve on the gerry rigging and fill with coolant. Drove it on to Ft Peck, fished a week and drove it back home about 1,200 miles in total to and fro on the patch work. Watched it like a hawk as you can imagine.
My humble suggestion, if you're past say 125k replace it.
Wow. What a ripoff! I've done it on 3 of these vehicles now and it never took me more than an hour - including the first time. Now it's more like 30 minutes, and that's if I change the heater hose with the wye in it all the way down to the water pump.