What is your definition of a crash? What causes a crash? In my case, my tank started to decline, and I lost a very large frogspawn... this caused a small ammonia spike which in turn killed my 5 purple Queen Anthias. Then I lost my cucumber from this second spike, and it was all downhill from there. The high Nitrates and Phosphates, and continued poor maintenance caused a huge HA explosion after that. If I had done my maintenance and taken care of the first small spike faster, it may not have happened. I think it is absurd to think that it is ok to lose your less than hardy inhabitants, and that it is ok to have a small slow decline in your tanks health. I would rather nip it in the bud, and do what I can to not have this decline.
Outy, I am not trying to attack you here at all, but there are a great deal of new people that read this forum, and I think that it is our duty to get them on the right track with good habits. With experience, they can adjust their routine over time, and what works for an experienced person with a well established tank will not work for everyone. There is much more to reef keeping than water changes, but it is one of the easiest things to learn, and has proven to lead to success.
In Paul B's case, he is very experienced, has a large skimmer, uses RO water and knows the WC schedule that works for him and his tank. In regards to the original poster, he was told that his system with no skimmer would never need water changes by an LFS. That is what we need to address here. All systems are different and will require different habits, but it is not a bad idea to teach new people the suggested routine, and let them adjust over time as they need to. Properly executed water changes will not hurt any system, and can only benefit the tank life.