Employment Expenses

If your employer doesn't reimburse you for ordinary and necessary expenses you pay, you may be able to deduct the cost as a miscellaneous itemized deduction subject to the 2% adjusted gross income floor. You can't deduct the cost of any item for which you would have been reimbursed if you'd asked for the reimbursement.

Which deductions qualify and why?
If you do end up paying out-of-pocket for job-related expenses, you may be able to deduct them on your return. In general, deductible expenses must be ordinary and necessary. An expense is ordinary if it is common and accepted in your trade, business or profession. An expense is necessary if it is appropriate and helpful to your business. An expense does not have to be required to be considered necessary.

Deductible expenses include the following:
bonding
physical examinations
office supplies not provided by your employer
professional or trade association dues
research, lecture and writing expenses
safety clothes and equipment
union dues
personal tools and equipment
travel, meal and entertainment expenses (see Publication 463)
computers and mobile phones (see Publication 946)

You must report these and other unreimbursed business expenses on line 20, Schedule A or on Form 2106.

Business Travel
The expense of your daily commute to work isn't deductible. However, if you find that you must travel to secondary or temporary locations — even within your metropolitan area — as part of your job and your employer does not reimburse you for that travel, those expenses may be deductible. Also, travel to and from a second job may be deductible.

Unreimbursed expenses for business travel outside of your metropolitan area may also be deductible. And you generally can deduct 50% of the cost of qualifying meals and entertainment expenses. You must complete Form 2106 to claim these deductions.

Home Office
If you use a portion of your home regularly and exclusively for business, you may be able to deduct expenses for that portion of the home, including interest, taxes, rent, insurance and utilities. You can deduct business expenses for the use of your home only if the use is for your employer's convenience. Special rules apply if your employer pays you rent for the portion of the home you use for business.

From H&R BLOCK