There can be any numerous reasons for a reinstall. Some people do it just cause they want to. There is no right or wrong reason really. It is a personal choice. I used to do it at least once a month. But i got out of that habit cause i dont have that kinda time to waste in front of my PC anymore.
I re-install it anyway i feel like at that time. Sometimes it is from an image, sometimes it is from scratch, sometimes it is a combination where i use an image of a clean install with only a couple programs installed. It depends on how old the iamge is, how much software has been updated since then, how many beta programs have been updated and so on.
If you really want to reinstall, go ahead. But i would seriously consider finding a better reason than the fact you installed a couple programs to the wrong location. That puts un-necessary wear and tear on your hard drive just for something as minimal as that.
