Timing Belt question

[RBbonfire]

The timing belt on my 2004 SC430 was replaced in 2014 at 92k miles.  Now, 8.5 years later, the car has 115k miles.  The repair shop is telling me it needs to be replaced because of the 8.5 years even though it only has 23k miles on it.  Are they correct?  They didn't inspect the belt.  They are purely looking at the amount of time since replacement.  Any advice?  I don't want to replace it, but I also don't want to take a chance on it breaking.  Can a visual inspection tell if there are problems?

Thank very much.

[RBbonfire]

Found and earlier thread discussing this question,

[Bodby]

The timing belt on the SC430, LS 430 engines are good for up to and above 100K miles in my experience from replacing the belt at 128k miles on previous cars, and the belts looked practically new.  I believe Lexus suggests the range of about 80K miles.  It should be replaced based upon mileage not the calendar.   

[RX400h]

There's an old saying that all belts and hoses should be replaced after 6 years. How many owners do that? At some point, rubber and plastics lose the plasticizing compounds within them, causing them to become hard and brittle. Fortunately, a visual and feel test can typically identify a ready-to-fail hose or belt.