Only if required. Only if you need it! there is no good evidence to suggest that it helps in otherwise healthy people. It may even be harmful by increasing bleeding risk. On the other hand if you have a history of vascular disease or if you have diabetes it helps decreasing risk of heart attack and stroke. Ask your doctor if it is beneficial for you.
Probably if no issue. Atherosclerosis is a natural process that depends on platelets to develop. That's why anti-platelet therapy, e.g., aspirin, is useful in patients with known disease. Even if one does not have clinical disease, there is some evidence that in men over 50 and women over 60 years of age, Aspirin (if no contraindication like bleeding risk, allergic/hypersensitivity) may help stave off the disease.