Very easy! Over the last few years, I'm actually spending about $16,000/yr out of my take home pay while working. I'm single, my projected retirement required spending including future healthcare, a car sinking fund, and long term home maintenance sinking fund runs about $22,000/yr plus a little more to cover income taxes. So that's my barebones budget to cover the things that I must pay for. $40,0000 would give me plenty of discretionary spending to really enjoy retirement, even without SS, so SS would be icing on the cake. Of course, despite that, my stash will allow me to spend closer to $70,000/yr after taxes with all income sources included, so I'm sure I'll really be cranking up the discretionary spending when I retire, but it's hard to imagine I'll actually spend as much as my stash will allow. For me, a likely relocation is a wild card as my expenses will most likely increase if I move.