As Don said, the annual is an inspection. It is my understanding that the Bonanza usually takes between 20 and 30 hours.
Some shops insist that all items "recommended by the manufacturer be replaced, overhauled, etc. If you are flying your airplane on part 91 (IE, not for hire) then you are not required to have anything done.
In my more than 25 years of ownership of a 1959 K35 (which is usually flown about 100 - 150 hours a year) my annuals rarely involve anything other than the inspection.
You will be pleased to know that the Beech is a well built airplane and rarely breaks.
Look at the old issues of the ABS magazine for articles written by Mike Busch. He will explain what I have said in much more detail.