1) Not considering Inflation

Retired individuals are the most susceptible to inflation rates as there most of the investment are into fixed income.
If the inflation decreases the purchasing power of money and retirees will be able to purchase less with their money than before.
So if your higher portion of the investment is into fixed income, make changes so that your investment rates are not less than inflation rates.

2) Not reviewing Asset Allocation

Asset Allocation is nothing but dividing your investment in a different asset class such as stocks, bonds, cash. Asset allocation is not a one time process and should be changed with income and time. Allocation vastly depends on the risk tolerance and time horizon of your investment.

3) Insufficient Insurance Cover

Having a right insurance is a must during the old age, or else one has to shell out more money to meet the high-cost medical expenses.

Individual must have a term plan as well as health plans even if your company is having cover for you. As insurance may be needed even when you are not working.

4) Neglecting Income Tax aspect

You may loose most of the interest part if you are not considering the tax aspect. Retirement products are taxed differently depending on the investment product and withdrawal procedures.

5) Debt trap

To enjoy the retirement phase one has to come out of debt. Make sure to pay your debt, plan your finances such that, there should be no debt when you enter retirement.

6) No Estate Planning

Proper estate planning is necessary if you want your wealth to be distributed rightly among the family members as per your wish.

7) Not creating emergency fund

The main advantage of setting an amount aside is at the time of need, one need not break the long-term investments made.