I tune for DX most of the time, unless I am engrossed in something, nearby the radio, such as replying to posts on QRZ.com, but cannot give the radio my undivided attention. Then I will glance at the monitor that is dislaying my logging software and see if anything interesting is happening, from time to time. What you said about some guys just wanting to make a couple of longer contacts, as opposed to running in pileup fashion is true. If I find someone calling who has not been spotted, and it sounds as though he wants a couple few more callers, I'll ask him first, before just spotting him. Some guys are grateful to be spotted. Others decline, and thank me for asking them first because they'd prefer to remain low-key.