I've used LR for years and like it a lot, so I joined Creative Cloud for LR and PS. Somehow I now have three versions of LR and two of PS on my hard disk. They appear to be complete programs, but with different file dates. Do I need to keep all these versions? They are confusingly labeled in Windows 7, for example.
Older versions are provided as some plug-ins may not work with the latest versions. However if this is not a concern and you don't mind CC desktop showing updates available to install, you could remove the older programs via the Windows control panel keeping only Photoshop CC 2014 and Lightroom CC 2015.