The last one is only good if you actually read it. I might end up seeing the first clause, assuming the entire line is irrelevant, and moving on without seeing

The last one is only good if you actually read it. I might end up seeing the first clause, assuming the entire line is irrelevant, and moving on without seeing the "Otherwise". Prefer declarative statements: "If you are 60 or older, you must fill form 445. If you are 59 or younger, you must fill form 331."