There are two sets of applications where I'm running into this issue:
- iWork, where I only have the new stuff installed because Software Update harasses you to install the new stuff if it detects you only have the old stuff
- Office 2016, which I've discovered fixes everything I liked about Office 2011
When iWork first came out I tried telling the system to open all .numbers, .pages, and .keynote files with the '09 versions of the applications by default, but it ended up ignoring that preference and launched the new versions anyway. As such I've gotten accustomed to just going to the Applications folder, opening up the old version manually, and then dropping whatever I want to edit into the open app.
Office is a bit more integral to what I do, however, and I'm really not looking forward to having to do more of this. Is there some sort of setting, terminal command, script, etc. that I can set to force the use of an older version by default?