If you don't gig, your gear will be covered under under normal homeowners contents coverage, but there's a big catch: if you don't have scheduled coverage*, you could be out of luck if you have vintage gear. In most cases, the company will pay you the replacement cost of a new instrument, not the vintage value. If your 52 Tele gets stolen, you'll get paid for a new 52 RI Tele or maybe even a new American Standard.
There's another possible catch: your policy may also have a limit on the total value of your gear even if you don't have vintage gear.
*Scheduled coverage means the items are listed on a schedule at an agreed upon value. The cost is usually reasonable. This is most often done on things like jewelry and furs, but it can be done on other valuables. You might have to have appraisals done on your existing gear.
If you do gig, then most companies will consider it business property and there will be limitations on coverage. Check your policy. [EDITED TO ADD: If it's business property, your coverage will probably be limited even if the loss happens at your house.] Some companies will let you buy more coverage on business property without having to buy a separate commercial policy.
Or you could just buy specialized coverage from
Clarion or its competitors.