Hi, Class of 2020. I feel like I have one leg in your class and one in the 2015 Class. I semiretired in 2015 to teach part-time online (flexible hours/days for 9 months) at half my salary, and while the purists don't call me retired, I certainly feel retired in comparison to my former work life.
It looks like the online gig will run out in May, so at that point I will be fully retired, even to the purists (paychecks will continue until Sept 2020).
In my case, this has worked out fine, since my 1/2 salary is equivalent to pretty close to what DW and I will pull down in SS, which I plan to take in 4.5 years. I can pull from DW's IRA in 3 years, so the next 3 years are the hole in the donut and I have enough cash in my 403b (and 8% of the portfolio in a brokerage account) to carry us to that point when I can pull from both accounts. I'll probably pull about 4.5-5% withdrawals for 5 years (with a lot of flexible spending in that withdrawal), but that seems manageable; after I draw SS it should go down to 3.5-4%, then drop even further when DW starts drawing.