...I'm 55 too....
...I have been in various businesses (primarily tobacco related) for over 40 years and for many years helped others start their own stores as part of a chain...choosing locations, stocking stores, ordering equipment etc etc
...thoughts
...it is tough to start a "part time" business....a new enterprise will take ALL OF YOUR TIME to get it off the ground... I have started many different businesses from the ground up and it takes time, capital and above all, desire to win the game...
...look for a business/venture that takes as little capital/start up expense as possible....in case it tanks, you don't lose your entire nest egg...
...don't start a business for your convenience, put it where your customers live/shop/and spend their dollars
...as stated in another post, if you have IT experience, that would be a good place to start looking at the possibilities
...never invest in another persons dreams
...never spend all of your capital on the start up.....there will always be more money needed than you think or planned for....always have reserves
...don't get involved in franchises....too much licensing and "the COMPANY" takes their percent off the top....
...don't buy lots of expensive computers when you start a business...you can run a successful business forever without them...
IDEAS...
...look for a successful local business that might be for sale due to retiring owners...NOT ONE THAT IS GOING BANKRUPT...
...PETS....pet boarding (Doggie Hotels) is a growing trend, especially in bigger citys
...lawn service....labor intensive, but not alot of machinery to get started
...auto detailing...several friends of mine make pretty decent $$$ detailing cars for individuals...fees run $80-100. per car...you can do at least 2-3 per day
...auto window tinting/pin striping/installing spoilers/stereos...combined with bolt on pick up truck accessories/bed liners...not much start up here either(most customers pay in advance and then you order the parts for them)...they do lots of work for individuals and also dealerships
ROI....Return On Investment....invest $10K to start a small service business and it makes $40K per year....the return on your investment is pretty darned good....invest $200K and make $40K, that sux....most of my retail stores make 200-300 % ROI....
...look at the simple things, things everybody needs, uses or wants every day....lots of opportunitys out there
...................hope you the best in the next chapter of your life