I thought my dreads were tight, why are they getting looser lately? - Dreadlocks FAQ's
Dreads don't go from loose to tight in one smooth transition. It's natural for the dread to adjust itself, going through tighter and looser periods. They start out as nice, tight knots. Not nice tight dreads (there's a big difference). The knots will loosen from there initial tightness after backcombing. This normally takes a week or two and a few washings. If they get very loose, or loosen very quickly the backcombing was not quite right. Usually you'll have several dreads with "special needs". If you know some of them need serious help check out this post about evaluating and rebackcombing dreadlocks.
After maturity the dreads have settled and tightened and they stay the same. Sometimes hairs will stick up away from the surface of tight dread. This is not the same thing as a loose dread. In the early stages you want to be sure that the center or core of the dread is locking. Don't worry too much about fuzz on the surface. It's cosmetic and it's easy to take care of later. What you do need to look out for is the actual body of the dreads loosing knots and becoming straight hair. If you keep the dreads free of all residue and clockwise new growth to help it lock (which you can start doing at your first "A" Week) this will never be a problem. Prolonged use of regular soaps or shampoos and neglecting new growth at the roots be make proper maturity slow and difficult. Depending on your hair texture it may prevent locking entirely.