Good Day.
Hope your day is going well. The kidney function testing frequency depends on your health conditions medicine that you take and your heart health and history. Every one is different.

Evaluating kidney function depends on the overall health status and comorbid conditions such as hypertension, diabetes, autoimmune and hereditary conditions. For these people, frequent monitoring is necessary for improving outcomes. While those with normal kidney health and no comorbidities, the frequency of monitoring will be very less.

Is there a particular reason for kidneys concerns ?
The things that affect kidney are taking too much Motrin and aspirin type stuff
Also high BP and High sugar will severely damage kidneys over time
Drink water and do labs once a uear

At least once a year, kidney function tests are performed on persons with diabetes. The frequency of testing for people with high blood pressure varies according to their degree of chronic renal disease. Testing may be necessary every 612 months for early stages and every 13 months or more for more advanced stages.

If you usually have normal kidney function, you can check her blood work once a year. If you have a decreased kidney function, you can check her kidney function every 3 months. It all depends on your level.