Every how many months shall i have my chest xray , breast ultrasound , liver ultrasound and bone scan?

Depends....: X-ray could be 1-2 yrs if nl. Breast ultrasound with mammo 1 a year if normal. Liver ultrasound don't need unless doctor asks for and then depending on finding radiologist will suggest follow up and bone scan also depends on findings 1-2 years likely.

Depends: If you are healthy, never. If you are sick, depends upon the disease and whether or not the scans change management.