Chris also had a habit of buying entire sets of various things because he wanted to use one or two pieces for retarded shit, so I'd imagine a lot of his sets aren't complete.
Good point.
Another thing about lego reselling: set is considered complette, if he had all of rare parts or set exclusive parts. Sometimes their are common parts in uncommon color. Sometimes they was produced only for few sets.
Let we think about set 6420. Go an open his page or brlicklink.
This set in use condition without box costs around 10 USD. It have parts:
- postman minifigure with unique torso - aroun 1 USD used;
- minifigure container (basket) BLACK - common as fuck, not worth a dime;
- common brick 2x2, worth even less than container;
- round plate CLEAR - worth nothing;
- two tille bricks with letter pattern - common, worth cents if in good condition;
- bicycle in yellow - set unique, in this color it was only in 6420. 5-7 dollars worth in acceptable shape;
- two pieces used to build a mailbox - rare with this particular pattern, but Lego produced many other mailboxes, so they worth is aroun dime to half of a dollar.
As you see, in pretty good set (really, this set has rare parts, is universal and usable both in MOC's, city dioramas in all styles and blah blah) most of its worth is in ONE piece, and if we think about TWO most waluable pieces (minifig torso and bicycle) they have nearly all worth of set. The most fragile pieces have the worth, and both of them are most likely to be wasted by Chris due to customization.
And this rule is in use for every single open/used lego set. Worth is in rare parts, not in the age of bricks (in most cases, sometimes a old brick will be worth more than new brick in the sime size, type and color due to slighty color changes over the years - but this is a very advanced concept). Most peoples which will wish to have used 6420 will not gave a fuck for the brick 2x2 nor tile with letter pattern - they cane use one from original set, or produced in 2017 as good. What they want is the postman minifigure (torso mostly, red legs are common, hat is common) and yellow bicycle. Paretto says hello in lego universe.
And word about boxes and instructions: they can double price of set. I'm pretty sure Chris didn't give a fuck about keeping in good shape instructions, boxes are now thrown away by cleaners.