Millions of retirees do their utmost to ensure that they get as much in Social Security benefits as they possibly can after they retire. Given how hard it can be to make ends meet on a fixed income, seniors have a lot of incentive to take advantage of opportunities to see their monthly checks rise in retirement.

For the most part, what you get from Social Security is defined largely by the decisions that you make both during your career and when you retire. Earnings history plays a key role in determining the size of your benefit, as does the age at which you start receiving monthly checks.

Yet there are some other factors beyond your control that can lead to your Social Security checks getting bigger. By being aware of those factors, you can ensure that you get what's coming to you in the event that you become eligible to receive larger benefits.

Three Social Security cards with key on top.

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1. When your spouse claims retirement benefits

If you're married, you potentially have two claims to Social Security benefits: retirement benefits based on your own work history and spousal benefits based on your spouse's work history. You're allowed to claim retirement benefits at any time after you turn 62 years old, with payment amounts adjusted for whether you claim earlier or later than full retirement age.

Spousal benefits, however, are only available once your spouse claims retirement benefits. As a result, if you claim your own benefits first, then there'll be a period of time when you're ineligible to receive any spousal benefits. Once your spouse claims, however, you'll suddenly become eligible to get your spousal benefits, as well.

Just because you can get spousal benefits doesn't automatically mean your Social Security checks will grow, because you're only entitled to get the larger of your retirement benefit or your spousal benefit amount, not the total. However, if you were married to someone entitled to substantially greater Social Security benefits than you, then it's possible that even a spousal benefit of 50% of your spouse's benefit will be larger than the full retirement benefit you get on your own behalf. If that's the case, your spouse's filing should boost the size of your check.

2. After the death of your spouse or ex-spouse

Another situation married couples inevitably face is what happens when one spouse passes away. Surviving spouses are entitled to survivor benefits, which typically match up with what the deceased spouse was receiving prior to death.

Unlike with spousal benefits, you're not automatically deemed to claim surviving benefits immediately after your spouse's death. However, if you do, then you'll get the larger of your own retirement benefit or the survivor benefit. If you're already getting a smaller retirement benefit and the survivor benefit would be larger, then claiming will give you access to the higher amount.

Also, those who were divorced after being married for 10 years or more can claim survivor benefits. If you remarry before turning 60, you lose the ability to claim those benefits on an ex-spouse's record. But if you stay unmarried or remarry at age 60 or later, then you can still claim survivor benefits after your ex's death.

3. If your spouse continues to work

We talked above about what happens when you first start getting benefits based on your spouse's work history. But even if you're already getting those spousal benefits, they can rise if your spouse continues to work.

Spousal benefits are based on your spouse's 35 top-earning years during an entire career. But your spouse can claim Social Security benefits and still continue to work. That claim gives you the right to receive your own spousal benefits. But it also opens the door to a potential increase if your spouse makes enough in the current or future years that one or more of those years breaks into the top 35.

If that happens, the Social Security Administration will recalculate your spouse's primary insurance amount. That, in turn, could raise your spousal benefit, which is based on 50% of that spousal primary insurance amount.

Get what's coming to you

Getting whatever you can from Social Security is important. When opportunities come up that could increase the amount you receive in your monthly benefit, you owe it to yourself to take full advantage. That way, you'll be able to have as financially secure a retirement as you possibly can.