I would recommend adding up the value of all of the items in your home, and buying a renters/home insurance policy equal to or greater than the sum total. If someone were to burglarize your home and steal all of your handbags, jewelry, etc., then the settlement you would receive from your P&C insurance carrier would most likely cover these items.
If you choose to insure individual items, then the items will be covered against loss or theft (outside of the home). For instance, if you were mugged, and someone stole your handbag and some of your jewelry, if these items had been separately insured, you would be able to get the value back from your insurance company.
Personally, I think it only makes sense to insure an individual item if it is very expensive and you think there is a reasonable chance that the item could be lost or stolen outside the home. If you have any jewelry item worth 10,000+, insuring the individual item would be a good idea. Keep in mind, you will need to have the item appraised, which usually costs around $100. Insurance companies typically do not accept appraisals that are older than 3-5 years.
Hope that helps!