use strict;

# Put all of the $usefuldata stuff in a subroutine
sub get_useful_data
{

  # Eliminated initial assignment of $usefuldata...
  # There's no need to calculate it if blah_blah()
  # is true and we're going to replace the value anyway

  if ( blah_blah() ) {
    # No need to store $usefuldata in a variable...
    # just return it
    return 2;
  }
  else {
    # Since blah_blah() is false, we return the default
    # case
    return 1;
  }
}

# Now we can calculate $usefuldata exactly where we want it
insert_into_database( get_useful_data() )