I have a really a good opportunity to buy a lange saxonia automatic big date moonphase for a good price from a family friend.
The seller purchased it used from a very reputable grey dealer without box and papers but has an appraisal report for the watch.
Im not too worried about the authenticity as you cant really fake a lange movement (if someone did kudos to them). But a lot of people are saying once you get into buying high end watches box and papers do matter and no matter how good the deal is you should not buy.
People have also stated that because of unknown service history, it could be a real pain the ass to take care of higher end watches as not anyone can service them and the saving for the purhase would be wiped out from the servicing cost.
What is the advice of the group here?
Box and papers aren't really important unless they document significant provenance, like if you have a receipt showing that some famous person originally owned the watch. A watch with box and papers is worth slightly more than one without, but that applies for both buying and selling.
All mechanical watches will need periodic servicing, and any second-hand watch could have an unknown service history. Obviously, more expensive watches are more expensive to service, so that should be an automatic part of your purchasing decision.