Strands need to be maintained which means you will work to untangle them from naturally shed hairs throughout the time you are wearing them and this can probably be done once weekly at minimum.
WHY THIS OCCURS: Your head naturally sheds its hairs at an average rate of 50-100 strands per day. You can identify a naturally shed hair by feeling a hard, round bulb at the end of it. With the extensions, some of these will be held in the bonds until you remove them when you will see whole lot of these shed hairs at once. Again, this is natural and happens with and without wearing extensions.
When those hairs are in the bonds, and when you are washing your hair, sleeping in it, those shed hairs held in the bonds became wrapped around one another and form these unions of two or more bundles being held together.
HOW TO UNTANGLE THEM: Take your thumb and forefinger and gently push the small tangle toward your scalp (this is the original way the shed hair was positioned before it was shed). Then, gently pull the pieces apart. You will sense the sort-of tearing apart, or separating, of the strands but you will be able to tell these are not attached to your head because there is no pulling that would hurt if you were pulling hairs that are attached.