Everytime I tot up our monthly costs, I shudder. Don't get me wrong, we can afford but it makes early retirement look a challenge and that's without a mortgage.
Council Tax £240
B/Band TV etc £100
Insurance Cars/House £150
Dogs Food/Insurance/Vet £150
Petrol £100
1st Car Lease £300
2nd Car depreciation £300
Utilities £200
Mobile Phones (x4) £50
Thats £1550 before we eat, clothe, go out or fund the children.
Currently I reckon we spend c£800/month on food, £100 on clothes, make up! and maybe £100 on birthday's/Christmas so call it another £1000.
£2.5k net is near £38k gross pay which is quite a lot of money considering that State pension at 67 is only c£21k for a couple.
Realistically you also need to factor in a depreciation factor on your assets also, for things like new appliances, soft furnishings, property maintenance, family events (kids weddings etc) and holidays. All of which is easily £500/month.
So I reckon to live comfortably as a couple with two grown up kids you will need in the region of £50k/year in today's money. Not quite the £72k quoted but that level would be subject to more tax anyway.
To have £50k gross a year you'd need a fund of c£1.25m excluding any state pension.
Personally my biggest challenge is to fund a gap between getting the state pension and a deferred DB scheme that kicks in at 65 as I can't see me lasting at work into my 60s!
As stated, most people underestimate their expenses and it can be a sobering exercise to actually track them, especially if you have two children!