A bunch of great advice has already been offered. A few more thoughts:

Consider the state of your health. A lot of guys start to slow down a bit sometime in their 50's. They don't have the energy and stamina they had when they were younger. Owning a business that requires hard, physical labor could become a challenge. It would also be wise to consider how much stress the business will add to your life. Sometimes our ability to handle stress declines with our advancing years. These factors do NOT affect everyone equally. I know a farmer who is 80 years of age. He is still out doing heavy physical labor every day! He can out work many guys half his age. He loves farming and plan to stay at it as long as he can! He is an exceptional man!

If you want a business that does not require you to daily manage it, consider a business that requires a capital investment. For example, I knew a guy years ago that owned some expensive, specialized equipment. He attempted to sell the equipment, but the market for it was very small and he couldn't find an interested buyer. Since he couldn't sell the equipment, He rented it to another business owner. This other business owner did NOT have the upfront investment to buy the equipment to enter the business. My friend was making some money with very little time or effort invested. Opportunities like this are not real common, but can be found at times. If you consider this option, get some advice on how to protect your investment.

Thanks for asking this question. I've been considering opening a business again. Having employees today sounds like it is even worse than it was a few decades back!!