My son has had tics off and on since he was about 3yrs old (He's now almost 8yrs). He doesn't have them all the time. He'll develop one which will last for a few months, then it will go away. Then a couple of months later, another one will show up and last another few months until it goes away and the whole process starts over. His tics have included neck rolling, knuckle cracking, sniffing, blinking, clearing his throat, shoulder rolling, nose scratching, etc. His current one is the neck cracking. He's constantly rolling his head and cracking his neck. He did have this tic about a year ago and it went away, then it came back, then went away, then it came back about a month and a half ago. He's slowing down on it (FINALLY) but, it's not completely gone yet.
The doctor said it is completely normal for kids this age to have tics. He said not to get upset w/him about it and that he'll grow out of it. He said the more I discourage him from it, the worse it will get and the longer it will last. He also said do what I could to keep him busy so it will distract him from the tic. For Ex: during his knuckle-cracking tic, I would have him do an art project or practice his spelling words. That way, he could do something OTHER than suffer f/the tic. Also, his tics would get worse when watching television. Especially the sniffing, throat clearing, and blinking. If you are really concerned I would suggest you visit with his doctor about it, but, just know there are a ton of kids out there going through the same thing.