True. You learn most of their "bag of tricks". For example, I missed one a day ago where there was a difference in the lapel. Never again. That was used in this puzzle also and I did NOT miss it. Lots of hairline differences. An ear missing. Something structurally different about doors or windows or furniture. Mouth or nose different. Sleeve or pant leg length change. Also, they usually space them out somewhat. When you find one, there usually isn't another right next to it so it helps to look elsewhere.
