Double Die- How Obvious Is It?

Questions of this type need clear photos before posting answers.

Not easy if the coins are worn to much and the Doubling is just slight. And what makes is worse is so many worn dies produce what appears to be doubling but is in reality just mushy looking letters and or numbers. The famous 1955 Lincoln Cent poor man's doubled die is an example. The last 5 and sometimes the last two 5's appear to be doubled due to a sort of shadow of another number. Just from worn dies though.
It would be best to look up all the different types of Doubling that appears on coins.