Two websites that sell all kinds of incubators say that styrofoam bators can be so unreliable that you should only use them if you can monitor them 24/7 for the full 21 days. We work full time so that's just not feasible. Are they really that bad or are the websites just trying to scare us into buying the way more expensive units? If they do need that kind of monitoring it'll be years before we could drop $400 for a pro unit. I'll have to build one or give up the dream of incubating our own.