Timing Chain

How often is the timing chain supposed to be replaced? I was thinking about what parts on my car I havent had replaced, replaced myself or had serviced and literally all I could think of was the timing chain. Since my car was a rental before my ownership it got beat to hell so, I had alot of bringing it back to life to do. Now that the car is almost brand new due to all 11k worth of work I have done to it(yaya stupid me) but it just gets to the point where you've put so much into it and the car wouldnt sell for that much so whatya do fix it n hope it works then it doesnt. Would that be a wise project to do?

I don't know when it's supposed to be replaced but I have 200,000 miles on my '99' with the original chain.

Do you have the 3.5? I would seriously start considering it at 200K. The one on my 99 failed about then. The one on my 00 looked ok at 172K. The one on my 06 SRX's LY7 high feature V6 is making noise on startup and I have to do that pretty soon.

I don't know but I imagine you might start getting some random misfire codes before a chain completely fails. I would think that would be pretty specific to the engine. On the LY7 most people get camshaft position sensor codes as a symptom of a stretched chain.

Yes, I do have the 3.5. When the chain on your '99' failed did it give you any warning or did it just fail? I'm not sure I want to put any more $$ into my '99' and I'm thinking of getting something else.