When to apply for Social Security is a tough decision because it has ramifications for the monthly payments you'll receive throughout your retired years. The earlier you file for benefits, the smaller your monthly payments will be. Waiting longer to apply will result in larger monthly payments -- but at the cost of missing out on those early checks. There are many factors to consider in deciding when to apply for Social Security, but the following three are crucial for nearly every retiree looking to take their hard-earned benefits.

1. Whether you're still working

Social Security retirement benefits are available as early as age 62, and you don't actually have to be retired in order to start receiving monthly checks. However, the Social Security Administration does have a rule that if you haven't yet reached your full retirement age and are still working, then you can forfeit some of your Social Security benefits if you make more than a certain amount from work. The limit is $16,920 for 2017 if you won't reach full retirement age this year, with the loss of $1 in annual benefits for every $2 you make above the $16,920 threshold. If you will turn 66 in 2017, then a higher limit of $44,880 applies, and you'll lose $1 for every $3 you make above that amount.

The Social Security forfeiture rules give you an incentive to wait until full retirement age to claim benefits if you're still working. In fact, the way that the rules work, if you make enough to forfeit your entire Social Security check for a given year, you'll be treated in the future in the same way as if you had filed for benefits a year later than you actually did. Once you reach full retirement age, you can work as much as you want and still keep all your benefits.

Social Security cards with brass key on top.

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2. Whether you have family members who will rely on your benefits

If you're single and have no one who can claim benefits on your work record, then making a Social Security decision depends entirely on your own personal and financial situation. However, when family members will rely on your benefits, taking them into account is important. In particular, understanding how Social Security works with your spouse can lead you to make a different decision than you would if you were thinking just about your own needs.

Spousal benefits are based on the age at which your spouse claims them, and so your decision about your retirement benefit has no impact on what your spouse will receive during the period when you're still alive. After your death, however, survivor benefits are dependent on when you chose to claim. Take benefits early, and not only will you get less, but your spouse will get less in survivor benefits, as well.

With more couples having both spouses with their own careers, the importance of survivor benefits has diminished in many cases. If the surviving spouse has worked and can claim retirement benefits rather than using the deceased spouse's work history, then the impact on survivor benefits is less detrimental to the survivor's finances. These provisions are particularly important in situations involving single-earner families, and you need to be careful about making sure your decision doesn't put your spouse in a potentially problematic situation later on.

3. What type of benefit you're claiming

Finally, the different types of Social Security benefits have different ages at which people are eligible, and the impact of waiting also differs. For basic retirement benefits, claiming between 62 and 70 is smartest, with the size of your check depending on how long you wait. For a spousal benefit, however, there's no advantage to waiting beyond full retirement age, which is 66 for those born between 1943 and 1954, and gradually rises to 67 for those born after 1954. So for those claiming spousal benefits, the best range is between 62 and full retirement age.

Survivor benefits have an even wider range. You can claim survivor benefits as early as 60, and if you're a disabled surviving spouse, benefits are available as early as 50. Social Security disability benefits are available whenever you or your family member is disabled, so claiming them immediately makes the most sense in the vast majority of cases.

Deciding when to file for Social Security is tricky, but it's worth the effort to make a smart decision. By keeping these factors in mind, you'll know what affects your benefits and whether it makes sense to file now or to wait.

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