I have been in saltwater for many years and have not done QT until recently. Years ago, I had a tank with about $1000+ in fish. I wanted to add one last fish, so i got a flame hawk. About a week later, I wake up and it is dead. I think nothing of it, but get home from work and two more fish are dead. Of course, the LFS is closed, so I have to wait until the next day to do anything. To cut a long story short, I ended up losing every fish within three days. It is no fun flushing $1000 down the toilet. I'm still not sure what it was, but I suspect Marine Velvet. Fast forward to present day...had a 75g set up and had just started stocking it... had an Eibli angel, some Chromis and added a bicolor Foxface. A few days later, the Foxface looks bad, the angel looks bad too. They were gone within 24 hours of me noticing them. This was MV. Not as bad a hit on the wallet, but enough is enough. I've got a 45g that I set up that will now be the permanent QT for all the upcoming additions to my new 240g. Also have a 15g hexagon in the bedroom that I may use for QT too. Its just not worth it to me anymore. A few extra bucks and a little extra time watching the new fish just makes perfect sense now.