There is a popular saying about health insurance: "Buy health insurance when you don't want it, because you may not get it when you want it." A vast majority of working age people depend on the health cover offered by their employers. While employers offer health cover, this may not suffice for these reasons:
a. Insufficient cover: With spiraling cost of healthcare, major diseases/ailments could cost a lot more than the insurance coverage offered by your employer. In the event, medical bills exceed your coverage, you will have to foot the difference. 
b. Loss of Job: In the unfortunate event of you losing your job – either as a result of retrenchment, unfavourable economic conditions, etc, - your health cover ceases to exist immediately. If you or your family members meet with a health condition that requires hospitalization during the interim period before you find yourself your next job, you will find yourself without a health cover and therefore will have to end-up bearing the cost of treatment yourself. 
Young people are healthy and have age on their side. They often tend to postpone or worse ignore purchasing a health insurance cover. While Insurance companies offer health insurance coverage for children as young as 3 months of age to a maximum age of 65 years, there are several advantages of starting early in health insurance:
No medical checkup: If you go for a health cover at any early age, you don’t need to undergo medical check-up – those under the age of 30 need not go through medical check-up (please note that this could vary from insurer to insurer). Insurers offer this concession to bring more young people into the health insurance fold. Also, the risk of health related concerns increase with age. 
No Right to Refusal: If you have purchased a health plan and continue to be subscribed by paying your premium within the stipulated time, the insurer concerned cannot refuse to renew your health plan on any grounds (provided you pay your renewal premium before the renewal cut-off date). The insurance regulator protects consumers on this front. Therefore, if your insurance claim increases over the years due to deteriorating health, you will still get coverage, even though it could turn out to be unprofitable for the insurer. 
Chronic Illnesses: Those with chronic illnesses might not get insurance cover at later stages in life. Therefore, it is prudent to obtain a health cover when there are no major health concerns. 
Waiting period: There are several ailments that do not receive health cover during the first couple of years of availing a health insurance. Think of this as a fair usage cap as is applied in the case of mobile phone data plans. Waiting period ensures policyholders do not unfairly use their insurance cover to the detriment of insurers. Waiting period prescribes a time-limit before a policy holder can claim expenses for treatment of certain diseases. This is usually up to four years with most insurers. For instance, if you are suffering from a Deviated Nasal Septum (DNS) – a birth defect (not a life threatening one, though) in the nostril which requires surgery for correction – then you might have to let the waiting period pass to go for this surgery. 
Diseases: Young people are prone to diseases too. It is a misconception that only older people are susceptible to diseases. However, that is far from truth. Epidemics, major ailments, and other diseases can happen to anyone and at any time. Recently, mosquito-borne diseases have spread at epidemic proportions across the country. These diseases lead to hospitalization and are at times life-threatening. Malaria, dengue, etc are recent examples. While cost of hospitalization is high, these costs can be avoidable with a health plan taken in time.
Accidents: There were more than 1.4 million deaths resulting from road accidents in the past decade. With such high fatalities, and an even higher number of road accidents, it is wise to go for a health insurance plan to be safe. 
Tax Benefits: The icing on the cake is that you can start availing tax benefits from the time you go for a health cover. So the sooner you opt for a health insurance, the earlier you can start saving on taxes. Payment made towards Health insurance premiums are eligible for tax deductions under section 80 D of the Income Tax Act. 
Now that we have discussed the benefits of starting early, it is important to exercise caution around the policy being sold. Read through the health plan wordings carefully to understand the policy and its offerings carefully. Health insurance plans come with exclusions – that is, certain type of ailments/diseases are not covered as part of the plan. Knowing such exclusions will help you determine what is best suited for your requirements. 
It is cost-efficient to buy a health insurance plan while one is young and free from any diseases. This is because you can avail a health plan at lower premium and with comprehensive coverage. The same plan when purchased at a later stage in life is much more expensive. Also, most health insurance companies have an upper age limit for their policies. Therefore, it is advantageous to start early. Compare health insurance plans online and be health insured.