Water quality, for breeders and especially for imports.. breeders and imports are more susceptible to get weak/sick/die easier than just regular pets. The damage they get, the stress, etc. So water quality on them is a must.. I change their water every other day and if I skip 1 day and do it the next, it's obvious they dislike it as they clamp up and lose color quick :(
Also, the jarring system - I tried the cheap/easy way and found it wasn't as efficient nor clean, so ended up having to spend more money to redo everything (heating wise). So find as many different ways to do the same thing as you can and go with what works best for your set up and time. Cheap doesn't mean better by any means.
And also, the time you spend.. for one spawn, once they are jarred you will spend hours near daily changing waters, feeding, etc... and if you have other spawns at different stages it adds up quickly. I didn't expect to end up spending 6+ hours easily a day with the fish once past the first spawn.
And lastly.. make sure you have made enough cultures - make plenty and then some of the worm cultures.. divide them up as much as you can, as you will easily and quickly run into trouble with just one spawn and not enough divided cultures. Adding BBS to the mix helps, but don't always rely on it - I prefer to mix their foods to give them a variety.