Come January, seniors may do a double take after seeing their Social Security checks. The 2% to 3% increase in benefits they usually get each year won't be there. The reason: For the first time in three decades, there likely won't be a cost-of-living adjustment. Though benefit amounts for 2010 won't shrink, with investment losses and lower home values, the lack of an increase will feel like a loss to many seniors. checks could be lower when factoring in premiums for Medicare Part B, which are deducted from monthly benefits. For most of the 42 million Part B beneficiaries, the...