From now on I intend to pick a night of the week and leave a recording device on, I certainly wouldn't have time to review an entire nights worth of data every day or it would be like a full time job, but if I pick a particular night to leave it out I can review the evidence over the following days.
I've also been taking photos inside the house to compare when I return from being out, so if something is moved I will know it. Between these methods and just being aware in general, I think the odds of capturing something is greatly increased.
Also thank you to the person that suggested audacity, I actually have audacity already, but I have found the the computer microphone is not very good at picking up sounds that are delicate or at a distance. I will try to find something suitable for the job, believe it or not the audio recording mechanism in the digital camera works pretty well at that sometimes.