I only clean my DSLR sensor when I am at home. Sometimes, when I'm on a long trip and I change lenses very often and there can be some irritating sensor spots on my photos.
At home, it takes some time to find all the sensor spots and "heal" them. Sometimes I don't see one and I have to adjust it later. My tip:
At the END of your journey (the moment you have collected the maximum amount of dust on your sensor), shoot one photo of the sky with a small diaphragm (F10 or smaller). At home, import that photo, increase contrast and you will be able to view the senors spots easier. Copy this layer onto your images to examine the spots. You can make circles around the spots in a separate layer with a smashing color to detect them even quicker.
Or, buy a camera with sensor cleaning functionality... :)