Mr. Lybrate-user, if one has diabetes mellitus, then regular blood sugar check up is necessary. One can do this test at home with a glucometer. Frequency depends on severity and type of treatment. Because if a patient is on insulin then very frequent testing is needed. Otherwise initially once a week, later at once in 15 days or so. Secondly once in 3 to 6 months hba1c% should be checked. Also periodically lipids (cholesterol) also should be checked. Also once a year get the eyes checked for any retinal involvement, this is a very necessary test.