Saving for retirement can be a slog, yet some people have a better time of it than others.

Planning ahead helps a lot. The best retirement savers are more than four times as likely to have given "a great deal" of thought about their retirement age, their lifestyle during their golden years, their future health-care costs and their financial goals than the worst savers, according to a new survey by Voya Financial, which scored more than 1,000 full-time workers on how prepared they were for retirement.