I have a full-time job that amounts to about 40 miles of commuting per day. I also have a home office from which I do freelance translation work, and I'll often make trips to the library to do my work there instead. So, I use the same car for commuting to my day job, personal use, and for business use.

As far as claiming business vehicle expenses...

I assume "commuting miles" is only referring to the commute from home to my (translation) workplace. But since I have a home office, it's actually 0... In that case, should I list my commuting miles for my day job as "other personal miles", since it's not related to my translation? Or simply under "commuting miles"?

Also, how dangerous is it to estimate the miles (this is my first time filing, so I didn't think ahead to keep any sort of records...)?

Any advice is greatly appreciated!