Humble suggestion: use the terse options when writing iteratively and the long form in scripts that you save to a file. The latter will likely be read by others or yourself in a few months from now, and it could be nice as immediate documentation if you did something fancy with a tool or option that you seldom use.

For instance, I know the handful of options that I personally encounter and use for the "grep" program, but the man page lists plenty that I do not immediately recognize. So typing them out in the script helps a lot with readability.

Going overboard with terseness or verbosity is obviously not helpful to the (human) reader, regardless of the direction.