We have a statement in our listing that says " Insurance: We have delivery confirmation on all U.S. shipping. If insurance is important to you, please contact us."
The reason for this is because some of our customers feel that insurance gives their package special handling. It may have sentimental value or is hard for our customer to find, and they want the added peace of mind. If they want it, we will work it out for them. Otherwise, we insure based on the value of the item to us.
Up to $50, we do not insure. If it is delicate or over $50, we insure it at our expense. In over 7 years of selling and 5,000+ items mailed, we filed one claim for insurance. We have absorbed the cost of damaged, but not insured packages twice. Not bad odds, and we ship a lot of old records that could be easily broken.
It doesn't matter if insurance is important to the buyer or not - if the item gets lost in the mail or broken or stolen you are still responsible to get that item to the buyer. Uner $50 or over it doesn't matter the SELLER is responsible.