DO notify the bureau of your new call as you upgrade. Please send SASEs with new call, in addition to SASEs with old call. DO include a SASE with any information request to the bureau. DO notify the bureau in writing if you don't want your cards. Don't DON'T send domestic US to US cards to your call-area bureau.
Overseas delivery is very slow.
Many cards coming from overseas bureaus are over a year old. DON'T send your outgoing DX cards to your call-area bureau. DON'T send SASEs to the ARRL Outgoing QSL Service. Don't send SASEs larger than 6 x 9 inches. SASEs larger than 6 x 9 inches require additional postage surcharges.