Washington » It took lawmakers a year to shape President Barack Obama's health care bill. If it passes Congress, it'll take the better part of a decade to write the user manual for consumers and doctors, employers and insurance companies.

Some health insurance consumer protections would go into place immediately. The big expansion in coverage comes in four years. About 25 million people would sign up, with most getting tax credits to help pay premiums. Ripple effects continue well after Obama has to leave office in 2017, if he's re-elected.

But even if the 2,700-plus-page bill passes, it's only the end of the beginning. Lawmakers will have to revisit hard choices they sidestepped.

Here's a primer on some of the major effects for consumers and other key players:

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Immediate changes » The bill pumps $5 billion into high-risk insurance pools run by the states to provide coverage to those in frail health. Taxpayer-backed insurance won't be free, but premiums should be lower than what's charged by private insurers willing to take those in poor health.

For people with private health insurance -- about two-thirds of Americans -- there would be some new safeguards. For example, insurers would be barred from placing lifetime dollar limits on coverage and from canceling policies except in cases of fraud. Children could stay on their parents' coverage until age 26.

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The self-employed » Starting in 2014, a health insurance exchange would offer a range of private plans to self-employed and people without employer-sponsored coverage. Small businesses could also join.

Once the exchanges open, most Americans would be required to carry health insurance or pay a fine. Medicaid would be expanded to cover childless adults living near poverty, bringing the total who'd gain coverage to more than 30 million.

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Seniors » Subsidies to private Medicare Advantage insurance plans would be targeted.

But the plan would gradually close the coverage gap in the middle of the Medicare prescription drug benefit. The plan also improves preventive benefits for seniors in traditional Medicare.

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Employers » The health care reform plan wouldn't require employers to provide insurance to their workers, but it would hit them with a stiff fine if even one of their workers gets a federally subsidized coverage. Companies with 50 or fewer workers would be exempt, and those with 25 workers or fewer could get federal assistance.

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Insurance companies » Health insurance companies would face unprecedented federal regulation and particularly close scrutiny of their bottom line. And in 2014, when the exchanges open, insurers will not be able to turn away people with medical problems or charge them more.