Keep track of your versions. Many professional programs (be it DAW, Notation etc.) by now offer to save versions of your project to be able to later revert to them. It is extremely helpful to actually write comments on these versions (about what is different etc). If you later on need to go back to a version of a track because something has changed, it is a nightmare to load version 2 through 23 just to find the right one. If you need to save new versions of a project in separate files, it actually helps alot to keep a log of the versions with notes on where the differences are. When big changes happens and you need to go back for whatever reason, that will be a huge time saver. A word of caution here: even if your software offers the option to save versions within one file, it might be a better idea to save a new file every time you change a version. There is always the chance that the one important file with all the versions might become corrupt and not be able to open up anymore.