Mastering might seem like too subtle of a process, since it's not as obvious of a task as mixing. Truth is, great sounding mixes can often be completely unprepared for playing in real-world circumstances. Mastering can be the difference between a song getting lost in the middle of a playlist or allowing its sound to sparkle.

A lot of mixing engineers and producers prefer having their work mastered by a pro, even when they can do that job themselves. That's because the clarity and perspective that an engineer brings to a mix can be a gamechanger in taking it to its full potential.