The manual says that the timing belt on my 2004 Saturn Vue V6 needs to be changed at 100,000 miles. Can I wait until it dies or is the Engine an interference fit with serious problems resulting if it breaks while I'm driving it.

The owners manual says that normal driving conditions the belt change is at 100,000 miles. Severe service schedule is every 50,000 miles.
https://my.gm.com/content/dam/gmownercenter/gmna/dynamic/manuals/2005/saturn/vue/2005_saturn_vue_owners.pdf

Well it would not be a bad idea but not completely necessary unless it is running awkward. If the timing belt wares it can slip out or rip and ruin the engine.100,000 is a fair amount of wear on one belt. The water pump is under the is behind the water pup housing. Due the difficulty, time and money involved with replacing one or the other it is usually best to do both at once as they are both right there. Your technician is telling the truth. Now your Saturn is not going to fall to pieces if you don't do this tomorrow but at 100,000 miles both are recommended. As for the cost, shops differ but it is a bit expensive. Not nearly as expensive as a new engine though. This is just a random guess $400 give or take. Let me know if this helps.

2006 Saturn Vue with a 3.5L engine V-6, Saturn recommends replacing timing belt every 100,000 miles, also replace water pump, due to it is timing belt driven, this is an interference engine which piston to valve damage will occur in the event of timing belt failure.Hope this was very helpful.

I have a 2002 saturn vue. Same thing..sounded like a jet engine ...loud humming as I accelerated . It got increasingly worse. It turned out to be the front wheel bearings. Replace them, now the noise is half as loud...have to do the rears also! 93,000 miles on it. Also, don't forget to replace the timing belt. It it goes too long and breaks, it will trash the engine...

This is not specfic to your car, but I think all have the timing belt to be changed at 60,000 give or take a few thousand. I have gone as far 100,000 on one.

needs to be replaced every 100,000 Miles

Both the 3.0 & 3.5 V6 engines in the Vue use a cam driven by a belt. Both are interference engines and the belt must be replaced at 100,000 miles. Warning: If the belt breaks serious engine damage will occur. The water pump is driven by the same belt so I highly recommend you replace it at the same time to save labor cost later on.

Time to change AKK belts also. Note thge timing belt service schedule in the owners manual.

How do i check the transmission fluid in 04 awd v6 auto

I work at a dodge chrysler jeep dealer, so I honestly don't know that you have a honda engine inside of a saturn vehicle, but I do know that dealerships are expensive. The belt itself isn't that expensive, but the labor is. A dealership would empty an ordinary person's bank account if they bough all the reccommended services. Transmission services or flushes would be helpful if you havent had one in a while, the timing belt is definitely needed, because if it breaks from old age, you could possibly damage your engine. I'm sure you keep your oil changed already. Spark plugs would be beneficial, maybe plug wires if you have them for your model. Maybe a regular fan belt and belt tensioner too, if you havent had that replaced yet. If He's offering the labor and parts all for 600, I would possibly consider that offer