It’s never necessary to wipe. The OSMC installer writes to the card at a block level regardless of what is on the card.
It really depends how complex your installation is, but you can always copy over /home/osmc/.kodi to the new installation. The rest, unfortunately, will be wiped by the reinstallation process, so, if possible, I’d recommend you install to another SD card. That way you still have your original configuration to hand as a useful reference - and it can become the installation card next time you need to reinstall.