Using length on a string will return the number of letters, numbers, symbols, and whitespace characters.
"Ben Something!".length()
Lists will return the number of items in the list.
Note that using length on an empty value — like "".length() — will return 0, while a list of empty values will still return the number of items.
Numbers will be formatted as strings before their length is calculated.
Dates, on the other hand, are seen as a single object, so will always return 1 when length is applied directly.