I retired September 30, 2016. I was 62 at the time. What has surprised me, and maybe we have just had bad luck, but unexpected expenses have really been a drain on our savings. I had to replace a driveway ($9,000), I am getting a dental implant ($4,000), my camper has needed several repairs (about $10,000 total), my wife needed hearing aids ($3,500), my cheap south end zone bleacher seat tickets turned into the most expensive tickets (Sukup) in the stadium ($1,700 plus Cardinal level donation). There have been others but things like this are just killers when you have no income at all. The only thing that has somewhat saved me is the stock market being up about 38% since I retired. But that is just a crapshoot, you can't time your retirement by predicting a bull market.
By the end of this year I will switch to Medicare and also start Social Security so that alone will make about a $2,500 a month difference in income/expense reduction. I guess if I have any advice, it's just to maybe keep working until you can take Medicare and Social Security. If you want to retire earlier then save up a boatload of money, I would think $2 million minimum.
But of course it depends on where you live and how you live. Here in Omaha our property taxes are sky high, sales taxes are high, gasoline taxes are higher than most states, car registration fees are outrageous. Small population means each person has to forfeit more cash to the City, County and State. Just these taxes cost me about $1,200 a month. So, there are just a lot of factors to consider for retirement. I don't know why anyone says you will need less money to live on in retirement. That has not been my experience. If anything, due to more traveling and vacations, you spend more. Sorry I wrote too much, but retirement needs a lot of thought and planning, at least I think so.