Once you’re offered a job, it may seem like common sense to accept it as quickly as possible, but that isn’t always the smart choice. Most employers expect potential employees to negotiate their starting salary, so you won’t start off on a bad foot by trying to get a better deal. That’s especially true if you’ve been offered a job that requires traveling, because the expenses of traveling could cut into your salary.

Determine the type of travel and how often you will travel. You will incur significantly more costs if you travel out-of-state rather every week than if you travel to a local city.

Ask the interviewer if the company reimburses travel costs. Most companies reimburse the majority of traveling costs for employees who must travel frequently, which would reduce the salary you should ask for.

Estimate the cost of miscellaneous expenses that will pile up because of traveling. Even if your employer does reimburse you for travel costs, it’s unlikely the company will cover expenses outside of room and board, plane tickets and gasoline costs. That means you’ll need to pay for day care, kennel, Laundromat, entertainment and other miscellaneous costs. Companies generally do not pay for family member expenses, should they travel with you.

Add up all applicable costs and translate them into yearly costs. For example, if you need to travel to a different city each week and pay Laundromat costs of $5 per week, entertainment costs of $20 per week and day care costs of $100 per week, your yearly expenses due to travel would equal $6,500. Day care is generally the highest cost, even if you only need to pay for a day or two. For example, the average annual day care cost for a 4-year-old in Pennsylvania in 2009 was $8,632, according to the National Association of Child Care Resource and Referral Agencies.

Research similar job salaries within your state. The best way to do this is by contacting someone who works in a similar position or by using online references, such as the U.S. Bureau of Labor Statistics, that provide a state-by-state breakdown of salaries. You generally don’t want to request a salary that puts you in the top 25 percent, unless you have a wealth of past experience. Stick to negotiating a salary that will put you at or near the average.

Present your information to the employer. Explain why you feel a larger salary is in order and highlight each cost you will incur. Always remain polite and never appear disappointed or angry if the employer decides not to extend a different offer to you.