Modern OE cooling hoses should be good for at least 10-12 years. Mercedes uses really good hoses so I have seen some that are still good after 20, 25, even 30 years.
But if it were my car after 10-12 years I'd change at least the upper thats whats goingto blow first. Around 15 I re hose the whole engine bay.
I'm slowly doing the SDL because most of the heater hoses in back are $80-$100 so I do one a year.
Only 2 left.