I believe the pump would be to take samples between changes, or to see how many more miles the oil could go if your running an extended change. As you mentioned at some point, if you have a Fumoto valve you can easily get a sample. A quick trip to a surgical supply store would get you the tubing and a small vacuum pump for about $12.00. If your running an after-market remote secondary filter and $130.00 worth of synthetic the $22.00 would be well worth it IMHO. If your running Rotella or Delo and a Fram or M/C from Wally World I would think you could just watch the odometer or calendar and figure it out.
yeah i agree i understand why some MIGHT want it...but at the same
time ive always questioned the accuracy of this method...
ive got a friend whos never pulled the drain plug on one of his cars....
sucks the oil out w/ a mity-vac

i wonder whats layin on the
bottom of the pan STILL when he does this...or if someone is getting
a sample from the top or BOTTOM of the oil sitting in the pan.
periodic (in between oil change) sampling can be done w/ a fomoto
valve too....for less than it costs for a 30 buck specialized pump.
if you like the pumping idea then buy a mity vac that you can use
for OTHER chores too (bleeding brakes would be a good start).
Mityvac