I find myself considering how likely a lottery win would be and how much would it take ? 
A lot
The average person would need something like £1.5M to sensibly give up work.
I managed on about £335k, but then I've taken a fixed rate, impaired health annuity with no spouse provision.
Makes sense I took a mix of a high risk pension plus a very low risk defined benefit one that starts next birthday. The high risks worked out in my favour.
My how big a lottery win does Jo/Jane Average need figure was based on
Average salary ~£30k
Average age ~ 42
Average years left to work ~24
Aspiration needed to give up work is the lump sum that would have to at least double the income for those working years. In practice no income tax and putting some money into a pension annuity pot would complicate it a bit
More importantly need to double it again if the plan is partner also stops work
Anyway 30x24x2 is about £1.5M and if partner stops it becomes £3M
A 25 year old on average earnings would need more like £6M