Dating bottles is free and it answers questions later that are otherwise unanswerable.
The other thing worth writing down is where a sample came from, because unlabelled vials become a mystery collection within a year and you end up throwing away things you liked.
For swatches: swatch on the paper you actually use, not on the paper that came with it. The same ink on two papers can look like two different colours, and the swatch is meant to help you choose.