David
You have your thoughts about calibration and if it helps you thats fine
They're not thoughts, they're facts.
but having owned the color munki photo what I found is that you waste good A4 photo print paper (it needs 2 runs to calibrate). Not only that it each printout has then have to be scanned each time at the right speed with a mouse.
You only have to do that once to create the profile.. you make it sound like you have to use twice as much paper

I think you've been using it wrong.
Also you have to stop using the colour management setting on the computer ( may mean deleting it altogether) but use the calibration one instead.
Not really... you shouldn't be changing anything on the computer to create or use a print profile. You create your print profile, and then when printing from photoshop, you select "Photoshop manages colors" and then select the print profile you created. You change NOTHING in Windows. If you've been changing settings on the computer, you've been doing it wrong. Unless you are referring to the monitor profile, in which case, yes, of course you do. You set windows to use the monitor profile you created, and no, you do not need to delete anything. Who told you that?? You just select the monitor profile in windows colour management tab and set it as default. That's correct.. if you don't do this, then your display will not use the profile... and therefore what was the point of creating a profile? I don't know why you're in there messing anyway, as the color munki software does it all for you. You have to change nothing.
I think you're a little confused as to what to do with your profiler
Presumably you have bought the color munki photo and use it as often as you say.
I've used it regularly, and still use at work. I don't own one any more.. I moved to the i1 system.
For me I can't afford to waste printer ink and good quality paper for any minor adjustments that I can't see any difference from before and after.
Again.. you only need to create the print profile once. You only need to re-profile if you use a different paper and/or ink.
Again I suppose you calibrate your printer at the same time with it and it depends on how good a printer you are using.
It shouldn't make any difference. It can profile any medium and ink. You're not profiling the printer, you're profiling the media.
The other problem is any picture on a computer screen is backlighted a hard copy isn't, so there is bound to be a variation between the two.
No, there isn't really. Technically there is, but a well calibrated monitor should have a black level of less than 0.2mCd/m2, and unless you are looking at a completely black screen, it's perceptibly black in contrast to the lighter parts of the screen. If yours isn't, it's not calibrated right.
The cost of color munki varies from £250 to £300 approx and and having owned one and sold it speaks for itself.
Well. from what you've said you were using it wrong, and you're the only one I know who's had any problem with it.
then I suppose one can afford to calibrate every 100 hours and not the number of printouts.
Realspeed
The 100 hours was for the monitor.. which costs nothing to calibrate. As I said, you only need to create a print profile once for each paper and ink set you use... that's ink and paper brand.. not each time you buy new.. so in effect, if you always use the same paper and ink, you only have to profile the printer once.. ever.. unless the manufacturer changes the formulation of their media.. which would be hard to ascertain unless they tell you, so I used to create media profiles every 6 months or so to keep current.