My bike was recently totalled. I am fully insured with Geico. The policy included $500 accessory coverage. Because I estimated having $2000 in accessories, I added $1500 in accessory coverage. Seemed logical.
Well, now that I need to cash in on that policy, here's how they say it works...
When they estimate the value of your bike, not only do they give you the depreciated value of the accessory, but they also subtract the depreciated value of the stock part it replaced (if applicable).
So, say custom risers and bars set you back $240. You bought them a year ago, now they're worth.. say $200. But you then subtract the depreciated stock risers and bars.. say $80. So you end up getting $200-$80=$120. Only needed coverage for $120, not $240.
Of course, they don't go out of their way to explain that to you when you ask for more coverage.
Maybe it works different if your insurance isn't with Geico.. but this is how it was just explained to me by one of their reps.