We are currently on SolidWorks 2009 and we are planning to install 2010 version this weekend. Everyone I read, it is suggested that remove SolidWorks 2009 first and clean up your PC and then install new version. My question is that what is wrong with installing 2010 first and then removes older version.

Last year, during same upgrade process, when I removed older version first, none of our custom add-ins were loaded when I put the new  version. I had to reinstall all add-ins on all machines individually. I believe that if I put the newer version first, my add-ins will be loaded automatically and then I can remove my older version.

I will be thankful if someone can point out down side of my approcah or any other suggestion,

Thanks