The ATO is critically looking at car log books to make sure they have been correctly completed. Generally you need to keep a log book for at least 12 weeks, and once you have kept it, you can in most cases rely on it for 5 years. It needs to record the following for each trip:

• The date it commenced;
• The date it ended;
• The odometer reading at the start and end of the trip;
• The kilometers travelled on the journey;
• The purpose of the trip (be specific – who did you visit and briefly state why)

You need to complete the log book entry as soon as possible after each trip, and keep a summary of certain other data.  It does not have to be a paper record – there are a number of apps available for your smartphone.

It’s not rocket science, but if you don’t do it properly you may have to say goodbye some handy car tax deductions.