This is a double whammy, because you not only have more years to pay for, but you end up with fewer working years to finance the retirement. Your later work years are usually when you earn your most income and can best sock away money for retirement. Traditional pension plans also are skewed toward late-career earnings. You'll also have more years for inflation to erode the value of your investments. Again, controlling expenses becomes vital.
Investments present another difficult challenge.
On the one hand, you have a longer retirement to finance than originally planned. Investing more aggressively can help make up for some of that shortfall. On the other hand, if you've retired earlier than planned for reasons such as a loss of job or health, you're probably going to need immediate cash flow from your investments to help cover expenses, and that means investing less aggressively. Consult your investment advisor on how best to go about this. Retiring early means more years until you qualify for Medicare.