In the next photo you can see the terrible finish again. You can also see that the used masking tape sticked to the fresh paint of the door while it was removed.

Of course, in general, paint jobs will be done better then this, so you will not find an example like this any time soon in real life. It does give a clear example of what to look for under or close to the rubbers.

Windscreen bonding
Also the sealing or the glue that holds the windscreen in place can give you a clue. Because the front and rear windscreen are in general not removed during a paint job, there is a good chance that some paint will find its way between the windscreen and body work. If this is the case, you know the car is resprayed.

Plastic parts
When a car has had a serious accident, these are in general the parts that are still intact. When they are placed back during the repair, it gives you a good chance to find colour differences.

For example, in the rear side panel of the body you often find a plastic fuel filler cap. If this body panel is resprayed, the colour difference will be striking when the filler cap is placed back.

Reflection
If the car is presented in a showroom, then you can use the reflection that the tube lights make in the cars paint. Because the structure of the paint determines for the most part how clearly the lighting is reflected, you can see the differences between parts of the car that are original and those that are resprayed.

Fine scratches
If a car has frequently been washed in an automated car wash, it will be covered with fine superficial scratches. These scratches are caused by the rotating brushes and cover the entire body of the car. When you discover body panels that are significantly less scratched, you know that these are resprayed.