Sheesh, how scary does that sound? These aren't really warnings about getting dreadlocks - Sorry Mom, you'll have to look elsewhere for that =] In fact, if you really happen to be a Mom looking for anti-dreadlocks info let me invite you to read the Note to Parents. Turns out dreadlocks aren't that bad...in fact they make more sense than straight hair for some people =]
These warnings are ways that you can hurt your dreadlocks if you're not careful.
Your roots are the future of your dreadlocks. You need all that hair to continue growing a dreadlock as large as the dread you are growing now. Less hair means less dread. Remember: "Every hair is sacred, every hair is great. If you cut a hair, Jah gets quite irate."
Anything that sits wet for a long time will grow mildew. That mildew will eventually die and dead mildew has a really nasty smell. Think "sour gym bag" or "old balled up wet towel". Take your pick, it's not pretty. Get your dreads dry in less than eight hours and you should be good to go. Residue free shampoo helps by not leaving residue that builds up and slows the drying of your dreads. Unless you have very thin dreads or you're not planning on keeping them more than eight months or so I would be super careful to only use residue free shampoo.
In general you want to be done with your dread comb by the end of the first week. Hide it if you have to! Re-Backcombing can be used to re-start a particular dread that has little to no knots. Such a dread has no real locking progress to loose so it's faster to re-start it than to wait around for knots to miraculously form on their own. Remember, whenever you re-backcomb a dread it is essentially 0 days old. Re-backcombing re-starts the clock on that dread and you should treat it as a new dread for maintenance purposes.
Conditioners make hair silky, smooth and hard to tangle. Hardly what you want when you're trying to make and tighten knots. A moisturizer should be used however, especially after the dreadlocks are mature and Dread Wax is no longer being used. This will prevent dryness and the damage and breakage that can occur from being dry.
Hair can take getting bleached if it's done properly. Generally though, if you begin bleaching you'll need to continue bleaching or you're going to have dark roots. When you beach the new growth be sure you don't re-bleach the previously bleached hair. If you do it will eventually cause breakage and you'll have dreads popping off. Not pretty.
This one really should be common sense. First off it's important to note that clean, healthy dreadlocks are no more likely to get bugs or lice than regular hair. The only difference is that if you do get an infestation it's harder to eradicate the buggers. For this reason it's worth while to be extra careful to not do silly things like sleep on the ground if you have dreadlocks, and you plan on keeping them. For the record I've been closely involved with dreadlocks since 1999 and I've only heard about a bug infestation 4 times. All four were campers that didn't use tents or sleeping bags.