Medical mileage only matters if your UNREIMBURSED medical expenses exceed 7 1/2 percent (0.075) of Adjusted Gross Income AND you itemize deductions.
Most people just take the standard deduction.
Itemizing makes sense if you are on the front end of a mortgage, have high state and local taxes, and/or make charitable contributions approaching the Biblical tithe.
I've been deducting expenses on Sched A for years, but the medical part just didn't add up to any benefit - until this year. I've just been diagnosed with Prostatic Adenocarcinoma, Prostate Cancer. The expenses are adding up fast.