The only time I replace my silicone hose is when I screw up and close a valve while flushing the lines from a faucet, putting a fat bulge in a line.
Bulges never go away.
THEN I'll replace that run.
I actually have two hoses that are at least 10 years old now - the ones that keep the HLT stirred.
They only ever have brewing water running through them - never wort - so they don't get the risky flushing treatment and they're still as white as the day they were made...
Cheers!