Timing Chain Replacement--How soon?

I have a 99 Chev Tahoe 4X4 with 100,000 miles on it. Back in the day it was recommended to change at 100,000 if it had not already broken. What's the word now?

I have a 99 Chev Tahoe 4X4 with 100,000 miles on it. Back in the day it was recommended to change at 100,000 if it had not already broken. What's the word now?
If it was mine and in ran fine I would keep om driving. I have 230K on one truck and 197k on another and neither have had any issues with the timing chain.