The annual federal employee benefits open season begins Monday, in which employees and retirees can change their insurance coverage and employees can set up flexible spending accounts for 2015.

The program of greatest interest typically is the Federal Employees Health Benefits Program, which covers about 8 million employees, retirees and family members. The FEHBP features 11 nationwide plans plus about 250 plans available regionally. Premiums vary widely and on average are increasing 3.8 percent for enrollees in 2015.

Eligible employees who are not currently enrolled in FEHBP may join the program during the open season. Retirees generally cannot enroll but like employees, those already enrolled can change their plans or switch between self-only and family insurance.

Both employees and retirees may enroll or change coverage in the separate Federal Dental and Vision Insurance Program during the election period that runs through Dec. 10. Enrollees can choose one type of coverage or the other, or both; premiums are increasing by about 2 percent on average in each. There are four vision plans, all national, and 10 dental plans, six of them national and the four others regional.

Although the government pays about 70 percent of total premium costs for employees and retirees under the FEHBP program — the U.S. Postal Service pays more for its active employees although not for its retirees — there is no employer contribution toward FEDVIP coverage.

Plan brochures, enrollment procedures and other information can be found at www.opm.gov/healthcare-insurance.

Under the FEHBP and FEDVIP programs, enrollment continues unchanged from year to year if an enrollee takes no action. However, one special consideration in the health insurance program is that several carriers that cover about 25,000 enrollees and family members total will be dropping out or restricting their coverage areas, forcing enrollees to choose a new plan.

In the flexible spending account program, a new enrollment is required each year. In that program, employees may set aside on a pretax basis up to $5,000 for certain dependent-care expenses and up to $2,550 for certain health-care expenses not covered by insurance.

There are two significant changes in that program for the 2015 plan year. The minimum set aside in each account is dropping from $250 to $100. Also, a “grace period” policy will apply only to dependent-care accounts; under that policy, costs can be charged to a plan year if they are incurred up to 10 weeks into the following year. For health-care accounts, a carryover of up to $500 from one year to the next will be allowed instead.

The flexible spending account program does not feature an employer share and does not apply to retirees. Detailed information on that program is available at www.opm.gov/healthcare-insurance/flexible-spending-accounts.