Before I answer, I need to know if you are a spy for the IRS.  

Yes, by pen & paper. Apps too cumbersome.

Absolutely.

I have the diary in the truck and sometimes get writer's cramp filling it out.

Yes and also volunteer miles. 

I love Carol Williams' answer.

Yes, absolutely!

Absolutely. I need it for tax purposes.  I use a paper log. It works for me. 

Will Hamm Yes, with a paper trip log.

Yes I do but I'm not out like agents are. 

Yes.  Serious tax write-off.

nope, company owns the car I drive for work.  I also own a personal car.

yes they seem to average around 60-70% of my total miles driven (thru the years ).

Yes, absolutely.

Yes, of course - don't you? *smirk*

I hope all agents  do it.

I do for three months out of the year.

Every day

No I have a lease car that is a total write off and a personal vehicle that we use for pleasure and fun.

You better! Yes, I do.

I do indeed, the old fashioned way with pen and paper

No, I have one vehicle dedicated to my business and two others as backup...

Yes I do and it is burdensome to do. 

I use my phone calendar then transfer to my paper calendar every so often. 

Yes, otherwise how would I defend the mileage I claim on taxes

I do, any tax write off is helpful.  At the end of the year it really adds up.

Yup!  And I love the Mile IQ app to track them.

Nope....I set myself up as an S Corp and lease....No mileage required--you write off everything--the payment, gas, repairs--the works...

The more ridiculous the car you own, the more the tax deduction....

Guys approaching or in the mid-life--this is an excellent excuse to buy something that would be otherwise totally stupid...

decades ago, I kept very good records.....as my listing duties changed to new construction, I didn't travel very much....my records were not as faithfully recorded....

Yes, absolutely.

You bet.

I use my car's odometer as it is used 100% for business.

YES, ...after Audit!

You bet

yes, tax deduction.

Will,

Yes, I used to use my calendar on my computer, but I now use Taxmilage. Very easy to use and the five dollars a year is worth it.

Absolutely 

Always, keep a small spiral notebook in my door and record before I take off every day.

Some days it feels like I drive to many!

I work with a business car. No need

Absolutely!

i do not, I have a couple businesses on the go and its difficult for me to divide up the miles into specifics.

Nope, through that idea out a long time ago

Our great land went metric a few decades ago.  I track business kilometres (or kilometers, take your pick) instead of business miles.

I keep a book in my center console of my car. I get in, write down the mileage, fasten my seat belt and start the car, in that order and do the reverse when I get back home.

Decades ago I had to do this. What a nusiance too. No way jose today