I've shot a 500C/M for 30+ years and my general handling of the magazine slide is to remove it for the first exposure, then replace it at end-of-role; unless I'm changing the back for another, of course. Therefore, I remove/replace the slide ONE TIME for the entire roll. However, I've watched several Hasselblad shooters on YouTube and all of 'em remove/replace the slide after each exposure. Why? Is it to ensure no possibility of a light leak between exposures? Just curious what you other Hasselblads shooters do...