When is it time to replace injectors

[Collingwood4me]

Hi every one ,
hoping for some expert guidance please.I have a 2004patrol tray back with 3100000 ks on the clock and was wondering if it’s time to change the injectors . To my knowledge (l bought it 2nd hand with 165000 ks on it ) they haven’t been changed , it’s still running fine with no problems , any helpful advise will be great appreciated
Cheers
Trevor

[jay see]

If it ain't broken don't fix it..

[Dhuck]

Welcome to the forum mate.