That may depend on several factors. First it depends on you. If you are a diabetic you should be seeing me every 3 months. If you are HIV+ then every 3 - 6 months. If you are on medications for hypertension, high cholesterol or hypothyroidism as examples, then usually every 6 months. If you are a healthy person on no medication, then an annual exam should be done every 1 - 2 years up until age 40 and then every year after that. If you are 25 years old and your cholesterol is reasonably good, it is unlikely to change in a year unless you gain 40 pounds of shrimp puff, cheese ball and beef patty weight.
I do order annual labs such as PSA once a year whether you do an official annual exam or not. Medicare does not really pay for annual exams and labs for healthy people. Many insurances allow for only one annual exam a year, meaning they will only pay for one visit and one set of labs a year. Since it must be a "wellness" exam, accordingly then you should be there to make sure nothing is wrong but not to actually evaluate anything that actually is. That is a cold, hard reality that both patients and doctors have been forced to reconcile one way or the other.
An annual exam should be done when you are not sick and generally focuses on whether your labs and/or physical exam reveal any abnormalities and on the best ways to prevent any from occurring in the future. If you have not had a regular physical exam since you tried out for your high school track team, then it would be a good idea to schedule one. It is better to find out about your cholesterol before it lets you know itself.