nandohyphen1 It depends. Obviously from strict security point of view you should replace it before it reaches EOL. Having said that one have to also consider other factors at play here, one of them as you properly mentioned is the potential threat model. But this also needs to account for attacks not aimed specifically at you, watering hole attacks etc.
To give some pointers (as I am not going to give you a definitive answer here) is to consider your habits, network hygiene and how probable is that you will be hit by collateral damage during your EOL time. To account for it, one may limit the sensitivity of data held on and/or actions taken on said device.