How long to replace EGR valve?

My egr valve failed at around 30,000 miles. The car is used mainly for my work commute on dual carriage ways and motorways. It does hardly any town driving/ short journeys, we use our other car for those journeys. The breakdown guy who first came to diagnose this problem knew what it would be even before plugging in his diagnostics, he said he seen quite a few of these valves failing and the cause was due to coolant leaking into the electrics of the valve, not helped by it's proximity to heat from the exhaust/dpf.

Mine failed at 30k just after i purchased the car. I assumed it was because it had been a motability car and had maybe been driven nice and steady for three years. I heard the same story about the coolant leaking into the electronics control from an AA patrol last week...... So could have been either in the end.