It was maybe an overgeneral statement that meant to communicate that unexpected things/expenses come up, in families with children, especially. However, if you've managed to remove the chance completely from your life...well..good on you, I guess. 
BTW, consistently ending up in at the end of the month about £100 quid out of your budget shows amount of discipline most of us could probably benefit from.
It was maybe an overgeneral statement that meant to communicate that unexpected things/expenses come up, in families with children, especially. However, if you've managed to remove the chance completely from your life...well..good on you, I guess. 
BTW, consistently ending up in at the end of the month about £100 quid out of your budget shows amount of discipline most of us could probably benefit from.
Hi Mort,
I agree with your second element there, perhaps I should've written in my first response - I 'tend' to disagree !! - of course, I'm not looking to argue with you. To align our responses in benefit for the OP and anyone else researching this topic - A 'good' budget will include an 'emergency' stash for unforeseen eventualities, Boiler packed up and just out of warranty, car gearbox, roof caved in, kids needing extra elements etc etc etc.
I understand of course not everyone will have a emergency stash or a good reserve in this way, but I previously, and still would of course, strongly suggest it when it comes to preparing and evaluation income/expenditure when working on a budget. I've also previously mentioned this in similar threads on the forum.
Hope that clarifies things a little more!
Cheers! DtM! West London & Slough UK!