In the last two weeks I have written more than 200 QSL cards. Mostly for more than 1000 Miles per Watt QSO's. Yesterday I brought a pile of 7 cm (2.75") to the QSL manager.
I still send paper QSL's for nearly each 1000 MPW QSO's, so the HAM that I worked with very low power, can read all the info on my card.
To calculate the distance and Miles per Watt, I always look up the QTH-locator on QRZ.
I noticed that more and more stations use LotW or will send the card only direct for $2. So now I also use QRZ, to look, if the station will answer a QSL via the bureau or eQSL.