Clean Image Sensor
Explanation: You can try a cleaning of the image sensor here if you see small spots on your picture, caused by dust. When cleaning the D7000 tries to shake dust off in the true sense of the word and this works best if you hold her upright, as you normally hold the camera when shooting.
If this will be successful is questionable because the default is that the D7000 does the cleaning already whenever the camera is switched on or off.
Tips: Regular cleaning of the sensor cannot do any harm, leave the standard setting.
But this should not cause you to be any less careful to avoid dust getting into the body!