Usually I look at many programs available that can be used in Linux and download and keep them in a directory called "Software." I can then create a desktop Icon with a link to it and run it from the Software directory.
Over the years though you bring down software with the stuff going everywhere at some programmers whim.
Some favour sticking it in "opt" directory . Some in "etc" some in "local" and so on and on . Its a bloody mess.
Some ,probably the most, integrate it into your /usr/bin directories and all the variations of /lib directories . What a bloody nightmare when you want to get it out. The automated removal tools always seem to remove a vital bit of some dependency and breaks your system.
To you programmers out there the one I find most sensible is the "opt" directory for everything and link to that place. That way if I want to clean out my savefile I can just select the main file in "opt" and delete it . If there were any dependancies used from my file system then they are still there unadulterated after I delete the software.