Mastering has changed in recent years, going from using a physical master copy (usually tape) that would ensure that every copy of the audio would sound the same, to being a tool used for rounding off the recording and cutting off the rough edges.
The goal of mastering is to make sure that your music sounds good in every situation, through every speaker, whether that be in the car, the club or at home through a stereo setup. If that isn’t reason enough to see it as important, then keep on reading…
Your music isn’t going to sound the same to you as everyone else, with acoustics, mixing skills and speaker quality having an effect on your impression of it. Mastering makes you take a step back and fix any glaring issues with your music that you may have missed in the mixing stage. You don’t have to master it yourself though, getting someone else to do it for you will be benificial too.
Furthermore, it can be argued that your music isn’t really finished until you master it, because, without the polish of mastering, the audio might not sound as good as it can. It doesn’t make a whole lot of sense to take the time to craft a song that you’re proud of and then let yourself trip at the final hurdle. Actually, that’s probably not the right metaphor. It’s like you ran most of a hurdle race, then stopped at the final hurdle and just walked sideways off the track, not even finishing in the end.
Do yourself a favour, master your tracks.