I know this has been asked and answered before but can't find the reference.  Question is, does replacing the Content affect my addons or will I have to reinstall them?  I have many addon planes and would hate to have to reinstall them all.  Thanks.

Jim

As far as I can say, airplanes are not concerned. Airplanes with their own effects or gauges which are stored in the default P3D folders are not affected as long as you don't delete the folders manually. P3D uninstall re-install does not touch files and folders it does not know. Only add-ons like ORBX Global or maybe Vector have to be re-installed if they were not using the "new" add-on.cfg installation path. I'm doing complete uninstall/re-install since 4.x and never run into problems.

If your add-ons are installed via the add-on.xml method (that is, they are installed outside the sim directory, usually in c:\users\<your username>\documents\prepar3d v5 add-ons) then they will be untouched and the sim will pick them up after re-install. 

If you have some add-ons on another drive or other non-standard place, say, you may need to manually add the discovery path back into your main add-ons.xml in either c:\users\<your username>\appdata\roaming\lockheed martin\prepar3d v5\add-ons.xml or c:\program data\lockheed martin\prepar3d v5\add-ons.xml (I recommend the former). Or you could just back up both add-ons.xml files from the locations above and copy them back over the newly-created ones after install.

If your add-ons are installed in the sim folder itself, things can be more complicated. It depends whether they modify any files in the sim that the content update will overwrite again (like Orbx Global Base, for example). In which case you need to know what those files are and back up your current versions, or do a reinstall after the upgrade. Have a read through the other upgrade threads here, though, because in some rare cases this can cause problems. If your add-ons don't overwrite any files in the sim folders but just install themselves into the sim folders (like most aircraft), then the uninstall and reinstall of the client and content should not touch them at all. This isn't a 100% guarantee that they won't need some post-upgrade attention, though. There are so many different methods by which add-ons install that you can't cover everything. Personally, I back up my entire sim folder before I upgrade, just in case I need to grab any of the old files. 

Personally, I agree with the advice to uninstall the whole sim and reinstall all elements this time around. It definitely gives better results.

Generally speaking, though, you shouldn't need to reinstall much of anything.