Not sure the exact way they calculate depreciation but it's a formula based on age and i think my agent said they actually google for current selling prices and then depreciate from that price. Yes, keep all receipts and serial number in a safe place (shops you by from usually have them on record too). Cops need serial number and you should register it online too. All i had to do to file my claim was tell them what happened, send a list of items, include approximate price and age, include supporting documentation of ownership (photos of the item showing brand, receipts, etc.), and the police report number. With my bike, it was only 1 year old so not much depreciation and all part swaps were done at the shop during purchase so i had 1 comprehensive receipt. I'm also claiming the damaged rack and lock. Insurance check and new bike will be here next week - got the exact same one because it was so awesome. If they ever recover the stolen one, there will be a sweet MTBNJ deal for somebody when i sell it. Detective has been in contact with me and said they're checking surveillance footage from the area.