All I will add is the only time I've ever had infections in my beer has been when I've used fermenters with spigots.
It just seems to be next to impossible to properly sanitize the spigot prior to secondary/bottling bucket transfer.
I would spray PBW in there, StarSan, you name it. When it's hooked up to the fermenter, you just can't get the thing properly sanitized if you want to use the spigot instead of an auto-siphon.
Perhaps this was because I was using the spigot during fermentation to pull samples for gravity readings, leaving some attractive sweetness in there for wild yeast/bacteria (even though I'd spray it with StarSan after taking a sample) but either way - be extra careful if you use the spigot to transfer your beer to a secondary/priming tank rather than an auto-siphon.