Ignorance is definitely not bliss when it comes to retirement saving. Despite the wake-up call of the global financial crisis, research shows very few people are clued up on just how they will pay for increasingly longer lives. A comparative international study shows that women and low-paid workers are most likely to face old age under-funded. But, according to Olivia Mitchell, an insurance and risk professor at the Wharton School, it's time for everyone to defer retirement plans – perhaps to age 75. Forget about putting your feet up, she says, instead opt for a more comfortable lifestyle and staying mentally astute.