After adding my sets, I want to add my parts to Rebrickable, since I have lots of parts bought on Bricklink.
But since I don't keep them separated from sets, it would be difficult to count how many parts I bought which are not from sets.
If Rebrickable offered a view of parts for inventory checking, including both spare parts and parts from my sets, I could easily compute how many spare parts I have.
Example: I have sets A and B in my sets, which contains respectively 10 and 20 of part X.
So, "Inventory check" page shows me counts for every part, so it shows me that I have 30 of X.
I count my parts, and I see I have 45 of X, so I need to add 15 (45-30) of X to "my parts".
It seems reasonable to me to have it, and also rather easy to implement.
It could be accessible via a link or a checkbox in the page "my parts".
What do you think?