I think my husband's parents are a good example of what happens when you don't plan.
Both of them came from somewhat well-off families and had certain ideas of what you were supposed to do and own to be considered successful - nice clothes, nice car, nice house, pretty things, jewelry.... Unfortunately, their career and life choices didn't mesh real well with their expectations of life.
FIL studied art in college, and went on to a life of sales and retail jobs (car salesman, appliance salesman, etc). He was competent at what he did, and I guess back in the 60's and 70's those may have been legitimate career choices, but as the world evolved, his skills and education did not. Before he retired he was assistant manager at the shoe store in the local strip mall. At one point he'd been offered the store manager position, but declined because he didn't want the added headaches and responsibility.
MIL went to college and got her MLS and a teaching degree in one state, but they ended up moving to another state for FIL's job and she didn't want to go through the hassle/work of qualifying to teach in the new state. She ended up getting a job as a secretary with the city and stayed there for pretty much ever. The pay and benefits were decent enough, and thank god she got a real pension, because they would have ended up destitute without that.
They lived in a relatively LCOL area, so even with their unexceptional career choices they made a comfortable enough living. Not rich, but comfortable. Unfortunately, having grown up in well-to-do families, their expectations were larger than their paychecks. They liked stuff. There was never any one single crazy large thing they bought that sent them over the edge, it was just a general lifestyle that was beyond their means.
They were always buying new clothes, because you have to look nice. Grocery shopping - buy whatever you feel like eating, don't worry about sales, coupons are for poor people, the expensive one tastes sooo much better than the store brand, etc. They replaced their cars (of course they needed 2) regularly, because you can't drive "an old junker" like the "Mexican dishwashers" who lived in the next building over. Something broke? Call the repairman because you can't possibly fix it yourself, or better yet just buy a new one.
They always managed to spend all their money and lived paycheck to paycheck. If they had money leftover after paying the bills, they would find crap to spend it on. Of course this meant that if there was ever any snag or hiccup, it was a crisis. But that's what credit cards are for, and as long as you make the minimum payments you're doing fine. My husband once told me with pride (before I dragged him kicking and screaming into Mustachianism) "No matter how bad off my parents were, they always managed to take us out to eat at a restaurant once a week." It was pretty eye-opening for him when I pointed out that maybe that's partly why things were bad in the first place.
Somewhere along the line, after hubby had moved out and was in the Navy, FIL lost his job and things got pretty bad for them. They almost lost their house, and only kept it because hubby gave them several thousand dollars from his re-enlistment bonus. They managed to hang on long enough to sell it and not get foreclosed on, and moved into an apartment.
FIL eventually got a job and things stabilized. So since they had spare money they took up the new hobby of "antique collecting," or as I like to call it - buying stupid ceramic figurines. They spent weekends driving all over the state, buying collectible plates and ceramic dogs and other stupid shit to fill up their apartment. And I do mean FILL IT. Every wall and corner had an expensive display case (with lights!) to hold the stupid shit they bought. When they ran out of space to display crap, it just sat in boxes in the closet, under beds, in the guest room, etc. FIL reveled in showing you each of his latest "pieces" and explaining that he only paid $200 for it, but "the book" says its worth $300! According to MIL, this was our inheritance! yay
As the years went on MIL had a series of medical problems, and ended up in a wheel chair. I guess they told her she should be able to regain her ability to walk with enough physical therapy, but it was hard so she didn't want to do it. Somewhere around here, they decided to buy a condo so they'd have a fixed payment. (This also gave them more room to store stupid ceramic shit. yay)
So they moved into the condo. And after a few years, FIL decided he should retire so he'd have more time to take care of MIL - who still had to get up and go to work everyday. I think it was more he was finally old enough to collect SS and taking care of MIL was just an excuse. Mom made it another year or so working and she finally retired with her city pension.
At that point though, MIL's health started deteriorating - she was showing signs of dementia. FIL cared for her at home. For the first few years it wasn't too bad, she was just forgetful and couldn't be left alone for too long, but she was mostly mobile and could stand to get in/out of bed or the shower and such. Unfortunately, it was apparently MIL who had managed all the finances for most of their lives. Left to his own devices, FIL managed to get himself in deep trouble. He ended up declaring bankruptcy somewhere in his early 70's. He was able to keep the condo and his car, and after the bankruptcy payments he had enough to get by on, but it wasn't much fun for him. His life was pretty much driving MIL around to doctor's appointments and sitting home watching tv. Although, except for the shopping this was pretty much his life before bankruptcy, so I guess it wasn't that big of a deal. The only good thing was that after much encouragement from my hubby and his sister, he started selling off some of his "antiques." (All of the kids greatest fear is having to deal with thousands of antique ceramic dog figurines when he dies). He started renting a couple of cases at the local antique mall to unload some of his collection. Unfortunately, he would often take the proceeds and buy something else instead ("But the book says its worth 2x as much as what they're selling it for!")
One winter hubby was talking to him and FIL mentioned that his furnace died. Fortunately, he had one of those home warranty deals and they would cover the cost of the repair. The problem was that he had to front the money for the repair and would get reimbursed at the end of the month, so he only had like $75 to last him a couple of weeks. He had just gone shopping so had a house full of food and expected to be ok, but there wouldn't be much fun for a while. I told hubby that if something came up and FIL needed the money we would loan/give it to him. But hubby was concerned that simply the stress of not having money on hand was a problem. I was more than willing to help, I'm not going to let anyone starve, but I didn't want to enable FIL's bad behaviors. I suggested we could do an "early Christmas present," and maybe send him a grocery store gift card so we know he wouldn't blow it on something stupid. Hubby wasn't totally comfortable with that so we ended up sending him a check. In order to not sabotage our own financial goals, I basically re-allocated money I was going to spend on my family's gifts to the money we gave FIL, and got less expensive gifts for my family. Next time hubby called to talk to FIL, he thanked us profusely for the gift, and told us all about the model car he bought on eBay with it.
As the years dragged on caring for MIL became increasingly difficult, largely because she had become morbidly obese and stopped understanding things like standing or feeding herself. Several times she fell and FIL had to call 911 just to get the EMTs to help pick her up. FIL finally started to admit he couldn't do it by himself and starting looking into assisted living. He found a very nice place that told him her insurance would pay for her stay, and he moved her in. We were all relieved that MIL would be looked after and FIL could have some semblance of his life back. (I feel the need to point out that we live 2000 miles away so weren't really in a position to help with the home care).
Two months later the assisted living facility came back and said "Oops - look like insurance doesn't cover this. You owe us $10k, and start paying us $5k a month or come pick up MIL." MIL came home. FIL finally looked into eldercare assistance, and was able to get a home nurse in for most of the day for a heavily subsidized amount that he could afford. Somehow, he managed to make payments and pay back the $10k.
MIL finally passed away last year. Then there was the big question of her pension - would FIL keep getting money? No one seemed to know what option MIL had selected when she retired! Who talks about that sort of thing? Luckily, it turned out that there were indeed survivor benefits and FIL would continue to get a check. Phew.
So now, at 80+ years old, FIL has paid off his bankruptcy and even refinanced his condo mortgage to a reasonable interest rate. Between SS and MIL's pension he can pay the bills and keep himself fed. His days consist of volunteering with the hospice care group that helped him with MIL, occasional trips to the antique mall to exchange his old antique ceramic dog figurines for new antique ceramic dog figurines, and watching copious amounts of television. He has just enough discretionary income to entertain himself buying stupid shit from mail-order catalogs. When emergencies come up, we lend him some money to cover it, and he stops buying stupid shit long enough to pay us back.
Aside from a lifetime of stress and uncertainty, I think the greatest price he's paid is simply the lost opportunities in his life. There's a lot of things he wishes he'd got to do - travel, spend more time painting, be able to visit us and see more of California... but he's got cable tv and a roof over his head, and I guess that's good enough for a lot of people.