I agree with Innovator. If you are going to QT, do it right the first time. Many wholesalers have disease and most animals come from a few suppliers. Some LFS
now QT and also treat their fish systems with de-wormer and copper but most do not.
As for inverts and corals, I think you all should reconsider. Ich can be brought into your sutem by other things other than fish. I used to be a person that never QT's inverts and corals. I have lost my zoos colonies via nudibranchs and I have treated for Red Bugs on my acros. Let me tell you that both of these issues are a PITA.
I have been in the hobby for almost 13 yrs with the last 5 being reef dominated. I was clean for most of that time but the last 2 have been very trying. With frag trading and the increase of popularity of the hobby, more parasites and diseases are being introduced. If it has not happened to you, it will. You *should* QT anything wet.
*180 gal Display, 100 gal basement sump, 33 gal refugium, 3x250 MH, 2x160 VHO actinics, zoos, some softies, LPS & lots of acros and other SPS.
*100 gal prop tank plumbed into main system w/ 2x96 PC lights and 1x150 MH,