I think having a serious QT setup and long routine is crucial- I got brook by skimping when I knew better. That took down my whole tank nearly as fast as I could ID it. Though the "in the works" rebuild is only 100g DT (for now) the system will be 250g+ and will have a couple of tanks dry but setup and 'plumbed in' so that if somebody looks sick OR if one of my LFS's has a sale I can make a purchase, get home and turn a valve to fill DT water into the QT, pull a sponge from the sump, stick it in the ready-and-waiting HOB filter and be in business before I take my jacket off. It's gotten to the point with designing this ultimate 'foolproof' (HA) system that operation, maintenance and catastrophe preparedness are now my favorite parts of the hobby.
That is exactly how I run my two hospital tanks.