Re: I've seen its like before
$time = Time to disinfect (hrs)
$rate = Hourly rate of techie (£/hr)
$cost = Cost of new device (£)
So it's worth chucking the device and getting a new one when:
$cost < $time * $rate
Given that the procedure that Joe User followed probably took about five hours, it's not worth buying a new device unless it's very cheap, or your techie is very expensive. Personally I charge friends "one meal" for this sort of thing, they shouldn't need to buy a new device unless they can find one for less than the cost of a meal.
What do you mean it was a rhetorical question?