And you need to differentiate between employee business expense and business expense if you own the business.
Speaking for employee business expense, there are many caveats as to what is legal to claim and a lot of it hinges on your current tax home and primary residence and the "expected" durations working out of town. IE, if you are just full timing and picking up work wherever it may be, then none of it may be deductible as out of town expenses as you are "home" at night.
On the flip side if you do it right and are in qualifying situations, living out expense tax deductions can be quite lucrative. I've been able to deduct sometimes up to $70-80k a year off my adjusted gross income. All without having to keep a single receipt, but rather just proof of location and durations.
You'll need someone well versed in this. Many tax preparers are clueless about it.