Combining health plans: when one employer plan beats two

Both of you are asking the right question from opposite ends. One of you is looking at the cost you pay every month; the other is looking at the cost you pay when life happens. A good comparison puts both on the same page, in dollars, for a whole year.

When you're allowed to change

Timing first, because it decides whether this is a now conversation or a later one.

• Open enrollment. Every employer plan has a yearly window. You can change then without a special reason.
• Marriage, birth or adoption. Under federal HIPAA special enrollment rules, explained by the Department of Labor, employer group plans must give you at least 30 days after one of these events to enroll a spouse or new child.
• Marketplace plans. HealthCare.gov allows a Special Enrollment Period of generally 60 days after a qualifying life event such as marriage.

Moving in together without marrying is usually not a qualifying event for an employer plan, and many employer plans do not cover unmarried partners at all. Check your plan documents for "domestic partner" before you plan around it.

The four numbers for each option

Open each plan's Summary of Benefits and Coverage, a standardized document every plan must provide, and pull:

1. Your share of the premium for the coverage tier you would choose (employee only, employee plus spouse, family).
2. The deductible, individual and family.
3. The out-of-pocket maximum, individual and family. This is the most you would pay in a year for covered in-network care.
4. Any spousal surcharge. Some employers add a monthly charge if a spouse who could get coverage through their own job joins your plan instead. Others exclude such spouses entirely.

Build the full-year table

Do this for each realistic setup. Here is the structure, filled in with placeholders, not anybody's real numbers:

Setup	Yearly premiums	Expected care costs	Worst case (premiums + out-of-pocket max)
Each on own plan	Your premium + theirs	Two deductibles may apply	Two separate maximums
Both on Plan A	Plan A spouse tier + any surcharge	One family deductible	One family maximum
Both on Plan B	Plan B spouse tier	One family deductible	One family maximum

"Expected care costs" is your honest guess for a normal year: prescriptions, routine visits, the physical therapy one of you already knows is coming. "Worst case" is the ceiling if something serious happens.

Look at both columns. The setup with the lowest premiums is not always the setup with the lowest worst case, and families with a known medical need often care more about the last column.

Things the table won't show you

Networks

If one of you has a specialist you rely on, search that doctor by name in each plan's directory, then call the office to confirm. A cheaper plan that drops a key doctor isn't cheaper for you.

Prescriptions

Each plan has a formulary, a list of covered drugs and their tiers. A medication on a high tier in one plan and a low tier in another can swing the math by more than the premium difference.

Health savings accounts

If one option is a high-deductible plan paired with an HSA, the contribution limit depends on whether you have self-only or family coverage. The IRS publishes the limits each year in Publication 969; look up the current year's figure rather than relying on last year's.

Keeping a backup

Dropping your own employer coverage can make it harder to rejoin until the next open enrollment. If job stability is a question for either of you, that's a fair reason to stay on two plans for now.

A way to decide

• If one setup is lowest in both the expected and worst-case columns and keeps your doctors, it's an easy call.
• If the cheapest premiums come with a much higher worst case, ask whether your emergency fund could absorb that worst case. If not, the pricier plan may be the calmer choice. See a shared emergency fund.
• If it's close, staying put costs you nothing to revisit at the next open enrollment.

Whatever you choose, write the numbers down and date them. Plans change every year, and next year's comparison will take ten minutes instead of an evening.