When entering rent/insurance/repairs/utilities for a home office deduction, should I enter the monthly rent or the total rent paid over the course of the year?

For all expenses claimed in a tax year, the amount should be the total amount for the year.  Regarding the amount to enter for rent for the home office deduction, you cannot deduct all your rent.  You can only deduct the percent of the rent as it associates with the space used for your home office.  Example:  You have a 1200 sq. ft. apartment and the room used for home office is 200 sq. ft. you will find the percentage you can claim by dividing 200 by 1200 and multiplying by 100.  So 200/1200 = 0.1667 X 100% = 16.67 %.  If your rent is $950 a month, $11,400 a year then you can only claim $1900.38 as home office rental expense.  You will use the same percentage for utilities and repairs to the home office or any area associated with it.