When most of us are recording our music, we rarely think much further than whatever deadline we're up against. The reality is, however, that with the rate music technology changes, often your mixes will end up being in 'obsolete' software within a couple of years. Most DAWs are pretty good about backwards compatibility, but problems can still arise if plug-ins you used no longer work in your current OS, if you change DAWs, or if, as is the case with Logic, you need your old dongle to open files created in the old, dongled version of the software. What happens if you lose it?
It is useful to try to think ahead and plan for this when you are recording in the event that you need to come back to the songs at a later date (to remix, to make a more up to date version to use live, or for an 'Early Tracks' type compilation like I am about to put out). So here are a few things you can do to help in that regard.
1.) Document, Document, Document!
I've mentioned this before, but it bears repeating. When you back up your songs (and trust me, you'll want to do this as soon as you're finished), take time to document as much as you can about it. Include the date of recording, the BPM of the song, the version of software you used to record it, the version of software you used if there is any data compression like .SIT or .ZIP. If you use multiple mics regularly, mention which you used on this project. Mention any hardware synths used and back-up their patch files as sys-ex data embedded in the MIDI tracks. It may seem excessive, but no one has ever been upset by having too much information when they revisit a song years later.
2.) Safety in Numbers
When you bounce down your tracks as audio, take the time to make note of the starting bar of each track. This is most easily done in the track name itself. If you recorded an SH-101 bassline that started on bar 17, for instance, name the audio file 101bass(17).wav. Many DAWs will do this automatically when you bounce down softsynths, but not when you're recording external audio such as vocals, hardware synths, guitars, etc. Just get in the habit of doing it. If you end up changing to an entirely different DAW in the future, you'll be able to easily reconstruct the track by importing the audio and dragging its start point to the appropriate bar. Another option is to simply record every single track for the entire length of the song, but this is a bit wasteful of disc space, if you ask me.
3.) Save Every Version Separately
When you're working on a song, any time you do something major, take the time to save it to a new, separate file. This way, if you make a mistake and ruin something that was fine before, all you have to do is call up the earlier version and you're good to go. All you need to save is the song file itself with the appropriate number on it. It's not a bad idea to keep a notebook or file on your computer indicating what the differences are in each version. You might be able to remember that easily now, but in a couple years, I guarantee you probably won't.
4.) Print Those Effects
If you want to really ensure your mixes will be replayable on your system at a later date, it's not a bad idea to bounce down all your audio complete with the effects on once your mix is completed. I'm kind of borderline on this one since it does take up more disc space, so what I generally do is bounce down anything where a specific plug-in is integral to the sound. If it's something that just won't sound the same using another similar plug-in, bounce it. This saves you the headaches of dealing with abandoned plug-ins that never get an update to a current OS or plug-in standard.