Don't use anything weird no matter how useful. I have works of writing I lost by using a specialized program that was used 'universally' years ago, now I can't load the program anymore on a modern system and nothing else will read the files.   There's a lot to be said for just using a text editor and storing in .txt or .rtf formats, they will still be readable for a long time.

WordPerfect is the favorite of many writers because you can control its codes easily. Word is fascist and hard to control. StarOffice / OpenOffice is free and will save/read those formats, plus store picture files a whole lot better.

Most software will let you 'CTRL-F' to search for words or phrases in a document, and you can get that Google add-on that lets you search your hard drive the same way(or some similar cheapware). That's the only extra bell or whistle I would want to make sure I don't lose track of my stuff, and it's already there.