The email arrives in your second week. Friday is the deadline, and the form wants you to choose between an HMO, a PPO and an HDHP, pick an FSA or an HSA, and set something called a deferral rate. Here is what each box does to your money.

The Window Closes And Stays Closed

New hires usually get a short window, often 30 days from the start date. After it closes, your health elections are locked for the plan year. The reason is the tax break. Your premiums leave your pay before income and payroll tax under Section 125 of the tax code, and the trade is that you cannot change your mind in March.

The exceptions are specific events, not general regret. Marriage, a birth, an adoption, or losing other coverage (aging off a parent's plan, a spouse's job ending) reopens the door. Federal rules give you at least 30 days after the event to ask, and some changes, like a Medicaid switch, get 60.

Doing nothing is a choice too. Some employers drop you into a default plan; others enroll you in nothing.

Five Words That Decide What You Pay

Premium is the fixed amount pulled from every paycheck to have coverage at all. You pay it in a year with no doctor visits.

Deductible is what you pay before the plan starts splitting bills with you.

Copay is a flat fee for one service, say $30 for an office visit.

Coinsurance is your share of the bill after the deductible. At 20 percent, a $500 bill costs you $100.

Out-of-pocket maximum is the ceiling. Once your deductible, copays and coinsurance for covered in-network care add up to it, the plan pays the rest of the year in full.

That last one caps less than people assume. Premiums do not count toward it, and they keep leaving your check after you hit it. A network plan is not required to count out-of-network cost sharing toward the cap, and care the plan does not cover never counts at all.

What The Plan Letters Restrict

An HMO keeps you inside one network. Out-of-network care is generally not covered except in emergencies, and you usually pick a primary care doctor who refers you to specialists.

A PPO covers out-of-network care at a worse rate and rarely requires referrals. You pay for that freedom in premium.

An EPO sits between them. No referrals, and no out-of-network coverage either.

An HDHP is a different sort of label. It describes cost sharing rather than the network, so it can sit on top of an HMO or a PPO. To qualify it needs a deductible at or above a federal minimum and a cap on out-of-pocket spending. That matters for one reason: an HDHP is the only plan that makes you eligible to fund a health savings account.

Run Your Year Through Each Plan, Twice

Compare total yearly cost, not premiums.

Two illustrative plans. Plan A costs $150 a month ($1,800 a year), with a $1,000 deductible, 20 percent coinsurance and a $4,000 out-of-pocket maximum. Plan B is a high-deductible plan at $50 a month ($600 a year), with a $3,000 deductible, the same coinsurance, a $6,000 out-of-pocket maximum, and $1,000 the employer deposits in your HSA.

Quiet year, $800 of covered care. Plan A: $1,800 in premiums plus the full $800, because you never reach the deductible, so $2,600. Plan B: $600 plus $800, minus the employer's $1,000, so $400.

Bad year, $30,000 of covered care. Both plans hit the ceiling. Plan A: $1,800 plus $4,000, so $5,800. Plan B: $600 plus $6,000 minus $1,000, so $5,600.

Notice how narrow that second gap is. Strip out the employer contribution and the traditional plan wins the bad year by $800. Low premiums win quiet years, low deductibles win expensive ones, and employer HSA money often decides between them.

An HSA Is Yours, An FSA Belongs To The Plan Year

To fund a health savings account you must be covered by a qualifying high-deductible plan, have no other disqualifying coverage (dental and vision are fine), stay off Medicare, and not be claimed as a dependent on someone else's tax return. That rule catches graduates whose parents still claim them.

The tax treatment is the best available. Contributions cut your taxable income, and money routed through payroll skips Social Security and Medicare tax too. Growth inside the account is untaxed. Withdrawals for qualified medical expenses are untaxed. Nothing is forfeited in December, and the balance leaves with you when you change jobs.

A health FSA runs the other way. It belongs to the plan year, and unused money is forfeited unless your employer offers a limited carryover or a grace period of up to two and a half months. A plan may offer one, never both. In exchange, your whole annual election is available on day one. A dependent care FSA is a separate account with its own rules, for childcare that lets you work. Skip it if nobody depends on you.

Life Insurance, And The Line People Skip

Employer life insurance is usually one or two times your salary at no cost to you. The catch is that it ends when the job ends. If no one depends on your income, extra life coverage sold at work is a low priority.

Disability is the line people skip, and for a young worker it matters most. Life insurance protects other people. Disability protects you. Short-term coverage replaces part of your pay for weeks or months, starting after a waiting stretch called the elimination period, often a week or two. Long-term coverage begins after a longer elimination period, commonly around 90 days, and can pay for years.

One tax detail matters here. If your employer pays the premium and you were never taxed on it, the benefit you collect is taxable income. Pay the premium yourself with after-tax dollars and the benefit arrives tax free. A 60 percent benefit that gets taxed replaces well under 60 percent of your take-home, so take the after-tax option if your plan offers it.

The Retirement Box On The Same Form

The same form usually sets your retirement contribution. If the plan matches 50 cents on the dollar for the first 6 percent you put in, contributing 3 percent hands back half of a raise you were already offered. Many plans enroll new hires automatically at a default rate, often around 3 percent, below the full match at plenty of employers. Find the match formula in the plan summary and set your rate to reach all of it.

Getting Through It In One Evening

The bottom of the form holds optional add-ons: legal plans, accident policies, critical illness coverage, identity protection. Each costs a few dollars a paycheck and pays out in narrow circumstances. Most first-year employees can skip all of them.

Here is the evening. Pull up last year's medical spending, or an honest guess at this year's. Run a quiet year and a bad year through each plan, premiums included, out-of-pocket maximum as the ceiling, employer HSA money subtracted. Take the winner. Set the retirement rate to capture the full match. Elect disability, after tax if you get the choice. Skip the rest.

Then set a calendar reminder two weeks before next year's open enrollment. Your usage will change and so will the plan's numbers, and this year's winner is not automatically next year's.