<human>: Hello, thanks for reading my post :D!  This takes place in Roseville, California.  I am having an issue with someone right now who has taken some of my items and is refusing to give them back to me.  I am creating a demand letter right now telling him to give me back my items or pay for all the items he has taken for me.

The problem is that a good amount of the items he took were used by me and most likely have depreciated.  The only way I could think of calculating the depreciated value of the used items was to look up the price of every item on amazon, then looking at what the item would cost if it were used.  My thought is that as long as the item does what it is suppose to do, I should be able to sell it on ebay or amazon for the same used price. 

The other bit that I am confused about is that there were a few items that I never even touched, or for that fact opened from the box, that he still has in his possession.  He has 2 car brand new car tires I bought from costco that costed me $220 ($110 each) which i never even got to see (other than a picture he sent me; an intel i7 cpu that costed me $265 at the time (haven't even opened it).  There were also a few items i bought off him (they were used), where he showed me what I was buying, I agreed that I would pay for them, then I sent him the money, but haven't even been able to touch them since I bought them.  Can I ask for the full price for these items or do i still have to depreciate them?

Can you condense the text into a few key points?
<bot>: how do you calculate depreciated value of items and are items that you never used/touch still get depreciated?  Thanks!