Do you align your documents? It is a good exercise for the sole reason that you can see how documents were translated by other translators. You can learn from the good ones as well as the bad ones. The main reason I recommend aligning is to have all your bilingual resources in one place. If you see a Spanish and English version of a treaty or convention on the United Nations website, it is better to have the documents aligned and ready to go in your translation memories. That way, when you are translating a legal document that refers to this treaty or convention or other aligned document, you can run a concordance (Ctrl + K in MemoQ) on a particular term or phrase and you're all set!
Many CAT Tools offer aligners, some complete and others not so complete. ABBYY has a standalone aligner that I find to be quite good. It offers you the option of exporting the aligned document either as a two-column RTF file or a TMX file you can later import into your CAT Tool. There is also an online service called NoBabel. The good part about NoBabel is its uncanny knack for aligning almost all segments in your files, depending on how close of a translation the target text is. (Sometimes the target language version can veer from the original with additions and/or modifications).
However, there is no fast way to align if you want to do it right. Sometimes the source text needs to be spell-checked. Other times, the target text needs work. If you don't supervise the alignment yourself, how are you going to know it was done correctly? No matter how long it takes you to align, you will pick up gems along the way that will save you time and improve your translation quality in the future.