Explain to me the importance of Box and Papers i nused watches

[docmri]

Hi,
I am looking to purchase one or two Rolex watches. These are watches I intend to enjoy and then perhaps leave to my kids to sell one day in the future. Some of the watches I look at have current models manufactured in the last five years. So, it makes sense to me that when looking to buy a more recent watch, I would like to have the papers /warranty card so I know how much longer I have the watch's warranty. I suppose the box is nice to have as well, although I am not entirely clear why this is a big plus in its favor if I plan to wear it or keep it on my winder. I guess I intrinsically understand it is a complete set, so that should be more desirable, but I am not sure how to evaluate how much $$ it should add to the price. Similarly, when I am looking to purchase a discontinued model (for example, a 40mm Sub that is no longer covered under warranty, why do I really prefer to have the box and papers? The only reason I can think of is to know for sure the year of the watch in case there were movement changes from year to year, although I wonder if it is possible to know the year of the watch's manufacturing without the warranty and papers? Nevertheless, is there any reason why having the warranty card /papers of a watch that was discontinued more than 5 years ago and thus is no longer under warranty is really something that should drive the price a few thousand dollars higher? Or, is it really necessary to know the manufacture date. I ask since I see a large discrepancy between box and papers watches versus without