That's a great question. I know the accumulation of old insurance policies and documents is a problem for many adults.
For property and liability policies, such as auto, home, umbrella, etc., you need to keep only the most current coverage summary page, called the "declarations." Your agent will keep electronic copies for years and so will your insurance companies. Once your policy period has ended and your current declaration has been replaced, shred the expired one. Also keep the most recent policy booklet -- the legal contract itself. From time to time, the insurance company will send you a new booklet because the insurer will have made some contract changes. When that happens, it's safe to recycle the outdated policy contract/booklet.
For individual life, health, disability and long-term care insurance and other policies that are continuous until they're canceled, you should keep the policy papers and any amendments until the coverage ends or is canceled. Since these policies often include the original application containing a lot of personal information, it's probably safest to shred the whole policy.
Hold on to group insurance policies, such as employer-sponsored health, disability or life insurance, until the insurer issues you a new policy or you are no longer part of the group or the group no longer exists. When it's time to get rid of those documents, shred any personal pages and recycle the rest.
There is one exception to the above tips: Keep an old policy for which a pending or ongoing claim is being filed or adjusted. You or your attorney may need the paperwork for reference.
I hope this helps you streamline your insurance file.