So next year on May 28 I become eligible for my minimum social security benefits which will be about $1,800/month.  I know every year I wait before taking the benefits, they go up roughly 7 or 8% .  That's fine. I see that from the online calculators/estimators.  My question is, do the benefits jump once a year, or if I start say in December would the benefits increase by 1/2 the amount had I waited a full year from my May 28 initial eligibility date?

The benefits are pro rated for each month between 62 and your full retirement age.

 

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You can retire at any time between age 62 and full retirement age. However, if you start benefits early, your benefits are reduced a fraction of a percent for each month before your full retirement age.

https://www.ssa.gov/planners/retire/agereduction.html

The main reason for the required telephone call to and from Social Security when you apply is to narrow down the exact month that you want your SS payments to start

 

I know when I applied the lady kept me on the phone for several minutes while she recited the amounts I would receive if payment started in 1, 2, 4 or 6 months and then asked me when I wanted my first payment would start.  Since the amounts were pretty close I told her to just start it on my birth month for full SS @ 66   

By month...not by year.   Use the SSA benefits calculator to show your percentages based on how long you wait beyond the age 62.   Just enter your birth year and see the results.

 

https://www.ssa.gov/planners/retire/ageincrease.html