How often do you "check out" other people?

How do you define “check out”? Which of the below is most suitable in your definition?

1) Check out: to look at someone’s features and determine their level of sexual attractiveness and to the extent you would like to “fool around” with them
OR
2) Check out: to determine how attractive one is, and to decide what is their desired features or characteristics.

So, how often do you check people out? Where and when are you most likely to? And what is your definition of “check out”? (Whether it is one of the above definitions, or your own)