I QSL 100% every month or so via Logbook of the World. Some 125,000 of my QSOs are currently listed there, so if you need my confirmation for an ARRL award chances are you can get it there instantly.

I also reply 100% to all QSL cards sent direct with SASE and/or postage enclosed, though sometimes it may a little time, depending on how busy I am. Otherwise, my practice is to QSL once a year via the bureau system, confirming all DX contacts that are a "first" for me with a particular station on a given band/mode combination (20CW, 20SSB, etc.)

While I appreciate every one of the QSLs I get via the QSL bureau each year, I do not want anyone to feel obligated to send me a QSL for each contact. If I need a QSL for an award, I will QSL direct and send an SASE or postage, as appropriate.