Odometer Reading
Do you use your vehicle for business? Or, are you claiming a vehicle expense because of your employment? If either of these situations apply to you, then you need to know the odometer reading on the vehicle you use for these purposes at December 31st. So, set a reminder to take a picture with your phone of this odometer. The picture will be dated and will provide some actual proof of the reading at year-end.
When we do vehicle expenses for tax purposes the mileage logs are not always carefully prepared, so having any documentation of a real number will help with convincing CRA this is a legitimate claim for tax purposes. If you took the picture of your odometer reading at the beginning of this year then you have two easily verifiable numbers. Of course, if you traded cars during the year, you need two more picture at the end of the life of the traded car and the beginning of life for the new car. Your phone is in your hand anyway, might as well use it to add some accuracy to your mileage log.?