More important than your flight itinerary is your contact info. If the tag on your bag with your info comes off, you'll need that contact info inside - on a big sheet of paper where someone will see it as soon as they open your bag.
Do you need insurance? If you buy insurance every time you check a bag, only the insurance company will be a winner. Although bags are occasionally delayed, it is very rare that they are truly lost and not returned to the owners.
The airline's liability limit for U.S. travel is $2,800. Any reimbursement you get for a lost bag will be based on the current value of what's lost, not what it would cost you to replace everything. Also, the airline won't cover a variety of valuables, such as jewelry, cameras, film, documents, antiques, medications and fragile items. Thus, you might consider insurance if you have valuables in your luggage. On the other hand, it's never a good idea to take valuables on a trip that you can't keep with you in your carryon bag at all times!