Fleur- I've got a list of oldies that I want & on my list I've got a price written down of how much I'm willing to pay for said item. It is really hard to not impulse buy. I want a bunch of stuff from Bon but then I look at my list and tell myself that I really should save that money for one of the bags on my list. I'd rather be able to pay top dollar for one of the items on my list when they become available than having something I'm unsure about now.
As far as insurance goes. Your talking to the right person. It's what I do for a living. The company I work for does specialized insurance for Jewelry, Body parts, Luxury goods on top of the normal stuff. This might be a bit over the top for you but here is what I do for insurance reasons. I've got a binder with an Inventory list of all the bags/smalls including their purchased value.. I've got a picture of me holding each item (important so insurance companies know you had it in hand) then I keep each receipt or if it was a trade I include a print out of what the retail value is at another site (HH, Bluefly, etc.) with a note of what I thought the approximate trade value was. I keep that in my safe at the bank along with a flashdrive copy of all the pictures & inventory list.
I'd start small and just start keeping your receipts in a folder tucked away in a fireproof safe and keep it as part of your homeowners/renters policy. I wouldn't seek out additional insurance until you've got over 6,000.00 in value.