Rising costs mean it's time to review your plan during open enrollment. By Kimberly Lankford, Contributing Editor November 7, 2008 Some of the largest insurers have announced whopping price increases for their Medicare Part D prescription-drug plans. Take a long, hard look at your current coverage; you have from November 15 to December 31 to change plans for 2009, and it may pay for you to make a switch. Average monthly premiums for Part D plans are rising by 12% -- from $25 to $28 -- in 2009. But average premiums for Humana's popular standard and enhanced plans are increasing by 60% or more. The average price for Humana's standard plan is now more than 329% higher than when it was first introduced in 2006, according to a study by health-consulting firm Avalere Health. And don't look only at premiums when assessing your Part D choices. For example, fewer providers are offering coverage for the so-called doughnut hole -- the coverage gap that starts after your drug bills hit $2,700 and lasts until your out-of-pocket costs total $4,350Qand most now limit that coverage to generic drugs. So be sure to compare deductibles and co-payments. The good news is that calculating your best option is easy using the Prescription Drug Plan Finder tool at Medicare.gov. Type in the drugs you take and the dosages, and you'll see how much you'll need to pay under the plans that are available in your area. Before selecting a plan, ask your doctor whether you're a candidate for switching to a generic medication; the coverage with the best deal in brand-name drugs may not be the best one for generics. Advertisement Or you could buy a Medicare Advantage plan and get coverage for all your prescription drugs as well as medical care from a private insurer. These plans tend to have lower premiums -- some as little as $0 per month in addition to your Medicare Part B premiumQbut may have larger out-of-pocket costs. The Medicare Options Compare tool at Medicare.gov shows which options are available in your area, plus average total costs based on your medical condition. For personalized help picking either kind of plan, work with your local State Health Insurance Assistance Program. The Medicare Rights Center also has a lot of great resources.