Sometimes, you can learn from your past and change your future. Other times, you really do need a time machine to go back and reverse the course of history.

Retirement is one of those goals you should ideally get right in the planning stages. But even when you do plan, you can find yourself in an unexpected place once you get there.

We asked three retirees what they wish they had known about retirement 20 years back. Here’s what they told us:

What I Wish I Knew About Retirement 20 Years Ago

I had put both of my daughters through college. So the period from when I was about 48 till I was 54, I was not saving because I was paying tuition. I thought I had 10 years to do some real serious saving for my retirement. But then I was forced to retire early. And you just don’t anticipate that your fate will completely change. It was like, ‘Oh my goodness, I need a Plan B. This is a lot more serious than I anticipated.’

Right now, it’s not like an emergency or anything. I have a roof over my head. I have good insurance. But inflation – it’s really taken off in the past few years. This is not the retirement I anticipated. And yet, I’m way better off than most.

I think most of the retired people I know, irrespective of their income, have come to live on less than what they’ve been accustomed to. And it’s very difficult to dial back your lifestyle.”

What I Wish I Knew About Retirement 20 Years Ago

“Maybe this is typical or maybe I’m just not up on this, but I was shocked to find out that I was eligible to receive my late husband’s social security’s benefits. I made the assumption that, because I had remarried, I couldn’t get it.

Turns out, not only was I eligible for that, but I would have been able to get social security from the husband I was divorced from, had I not remarried (even though he remarried).

Know as much as you can about government regulations. It’s not going to make us rich, but it’s enough to pay one of my mortgages.”

What I Wish I Knew About Retirement 20 Years Ago

I’m very comfortable in my current retirement. I get my 401(k) pension plan from my former employer, I get benefits from the United States army, I get Social Security. Plus, I have individual investments not tied to my retirement income.

But I didn’t realize the value the 401(k) would have on my retirement. If I had known, I would have contributed at least 15 to 20 percent to the program, rather than the 10 percent I did. If I had increased my contribution, my current retirement income would be substantially higher.

If you don’t take full advantage of the matching contributions from your employer’s 401(k), it’s just like leaving money on the table.”

If you’re retired, what do you wish you knew about retirement 20 years ago? Do you think the rules of retirement financing have changed since then?