At the level of compensation from Basecamp (at least what they say) it would be very easy to do that in 1 year: just put aside 50% of salary each month and you will have full 6 months of salary or (as you already lived on 50%) you will have one year of half salary to take time off.

Of course putting 50% aside is huge but I think 20% is achievable and will still create in one year a couple of months to live without a job.

I find myself sometimes hearing people saying things like this “if my company will give me X salaries I will leave” but few will actually do it. I always push back saying how about in the next 6 months you put aside some money and take 1 month unpaid vacation. I listen the arguments why they will not do it and realise people say will leave job if compensated but mostly they dont walk the talk as there are other risks/loans/friends/promises that keeps them there.

Except, here, you don't even have to save. You get to keep both the money you made over the past year and six more months of salary. Literally having your cake and eating it.