Yes be careful with torrents, they tend to immediately take up the space the moment you choose to download them, reserving that space. It's amazing how fast torrents can fill the drive up without realising. My recommendation is to save your torrents to an alternate drive if you have one. Same applies to the regular LW downloads. The incomplete folder can really bloat out in size very quickly. Arrange your folder by list & check for the incomplete folder & downloads folder sizes.

Another tip: Tip: Purge the Downloads Queue! (click on blue link). But only if your incomplete folder is out of control. Try not to remove incomplete torrents unless you are having problems getting sources/seeds for them to download from.