If the person is employed, then there would be some kind of reimbursement or medical cover by way of insurance. The reimbursement there would be only a particular percentage of the expense incurred. In that case another insurance cover can be taken for a reasonable sum, so that the residual amount not reimbursed by employer can be claimed from the insurance company. I such a case even a bancassurance, linked and tied up with with your bank account is also a suggestion.
But there needs medical insurance protection after retirement also. As generally existing disease are covered only after a period of four years, it is advisable to start a medical insurance about five years prior to retirement, and continue the coverage by proper renewal on time every year.
For a generally healthy person of age fifties it is preferable to have a family floater policy as it can cover the dependant family members also. However the premium will be as per the elder person's age. The benefit here is that the coverage will be available to all the members listed therein subject to overall limit as total. In case a son, or spouse or dependant daughter has a medical insurance policy which covers you also, then it is preferable to have a residual policy coverage to fill gap for the co-payment portion.(However this has to be properly discussed and made sure before taking a policy).
It should also kept in mind that whenever the coverage amount is enhanced subsequently, the enhanced cover comes into effect after the 'waiting period only'.
It is always better to take a insurance which covers some pre hospitalisation expenses, domiciliary treatment, charges for house visit, ambulance transport etc. However that will also entail higher premium.
So one should do a careful understanding and analysing the various terms and conditions and the premium difference for each ride and then take an optimum amount of coverage and also select the most apt policy plan.
One need not be scared of a policy needing medial test. and certificate. One should factually correct and honest in all the details asked for.
All parameters being same one should go for a plan that has coverage for long age say seventies and eighties. One should also decide whether 'cashless' admission coverage is needed and available.
To summarise the factors deciding medical insurance after middle ages it should be an optimum of maximum coverage, minimum premium, maximum age period covered, co-payment portion, cashless facility, domiciliary treatment coverage, pre-hospitalisation expenses cover,easy formalities etc. To select a provider, one should better go for the well established and reputed insurance company.
If buying through an agent, ask all questions coming to mind and get it cleared. Ask for alternatives and not just depend on the plans the agent promotes. If buying directly, then read al the fine prints and starred portions carefully and understand what 'is' and what is 'not'.