In defense of collecting them... One, okay... it's me we are taking about, nothing I do is normal, but for others... Usually if the stone is big enough, you know when it's gonna pass... The first couple of times, you are asked to collect them, so you do... But depending on the person, after that it tends to be curiosity... You retrieve it because you have terrible pain and you want to see what the hell this thing looked like... If a small parasitic alien tore a hole in your side and took off, and somehow that hole wasn't life threatening and the alien was now at a stage where it wouldn't harm you anymore, I could see a lot of people saying "Megh, it's gone, it's over"... But I want that sucker, it ain't going nowhere... I want that gut mauler on a stick, it's head on a plaque, stuffed and mounted.
I've talked to quite a few folks who have had kidney stones and at least six had collected and kept theirs... All have done it out of curiosity, only one was female and she is definitely a very curious/scientific person.
I think it's easier for males to collect them, with females it's probably less convenient/more awkward. A close freind of mine whom I grew up with was totally in agreement, she has never had them, but according to her "They are tiny little evil calcium children, you create them, they grow inside you and then they cause you horrible pain on their way out... You can't just abandon them... You don't flush your kids down the toilet... You may want to sometimes, but you don't..."
I also saved mine because it's a way of monitoring what they are like and if changes in my diet, water intake, etc make any difference... I've over time, I've managed to shrink them, make them less spikey and in some cases they've even been barely solid, almost crumbly... If I didn't retrieve them, I wouldn't really know what was working or if it was working well.
Incidently, I was recently talking with a couple of folks who also had them, and one thing I noticed was none of their doctors were very specific about water... They say drink plenty of liquids, make suggestions of what to avoid and tell you to flood your kidney with water... But never did any mention checking the mineral content of the water. What if you have high calcium content in your local water supply? I thought about it about a year ago, I remembered when I was a kid visiting my father in Italy, I drank some tap water and he said that was a very bad idea, if I were to do that, I'd probably get kidney stones in a few weeks... "Only drink bottled water around here" and even with that he only recommend one which he knew was neutral enough. I had forgotten about that, and in a conversation about water quality, it came back to me and I started wondering about it... Nobody whom I've asked was specifically told about bottled water vs tap water... I'm surprised because just using a simple test kit I've found our water is pretty hard... And mineral residue builds up pretty quickly on stuff half submerged in it. I guess it's something to consider if you have not been advised and get them frequently... I've noticed that with doctors, they tend to get used to explaining stuff one way and it becomes a spiel... But if you ask the magic question, you suddenly get this look like "um... eh.... yeah, I suppose I should mention that".