It depends on how fat the spending was prior to loss of income.
It you are already lean, concentrate on paying the mortgage. You can get help easier for utilities, clothing and food. Food especially- at least to supplement.
Haircuts are not necessary.
Lower the temp in house and make sure lights are off during the day.
Work hard to find the next job- that is your job.
If your children are in a county sponsored care program like SACC- notify them of the change in your income- they have a sliding scale.

Any credit card debt?

eating out
budget groceries
Cable
Cell phones - go to land line
internet
private school
rent out basement

in that order.

Cable, Friday night ice cream, Sunday bagels, kids allowances, twice a week cleaning lady, haircuts.

House cleaner for sure.

The biggest and most significant would be child care. We have discussed this, and we would likely still need some child care in order for the (theoretically) unemployed parent to look for a job, but we'd be able to wiggle that in around school schedules and play dates, at least for a while.

That alone saves like $30k a year.

Also, cable, activities, large vacations (would still travel to see family), and would try to slash our food bill by 50%.

I would cut things similarly to PPs, cut cable, eating out, etc. I would rent out the basement if things got bad.

Nanny, 70,000 car payment

Big ticket items would be:
stop college savings contributions,
reduce retirement savings to the match,
make a smaller payment on HELOC,
assess if we could eliminate either before or after care for the children,
stop health club,
reduce house cleaner to every other week (we have had her for many years),
reduce cable and eliminate a phone line

We do have 6 months emergency cash.

If we were concerned that this was a long term situation, I would see if we could refinance the house. We currently have a 15 year mortgage so our payments are significant.

I cut stuff during the federal shut-down last year, just in case (who knew what the Congress crazies would do?).

I cut most organic foods or more farm animal-friendly food (like local farm eggs)
house cleaner
outside entertainment
outside food

Vacations would go. And furniture purchases and other home improvements. But the real costs aren't that flexible in the short term. College tuition for 2 kids, mortgages and utilities on 2 houses. The second house would probably take a year to sell so isn't really a liquid asset. Coffee and diet cokes probably aren't going to make much difference in the grand scheme of things. We already don't have cable.

We don't have a lot of extra expenses, but I would cut Starbucks and small, unnecessary purchases at Target. My husband would pack his lunch more often.

Cable
New clothing
Eating out
Dry clean
Trips
Concerts,movies etc
Wine
Art
Cheaper household items (currently I have favorite detergent and favorite toilet paper lol)
I would still buy same skin care,and I wouldn't cancel gym membership ,maybe switch to cheaper one,otherwise I would be not only broke but fat and with bad skin

Recently lost half our income. So far:

Eliminated cable, and switched to lower cost internet provider, Got a $20 antenna from Target, and use Hulu Plus, Netflix, and Amazon Prime (already a member)

Reduced features on cell phone plan; delay in getting new phone even though mine is cracked!

Didn't renew expiring magazine subscriptions

I was spending a lot of money on beverages during the work day: diet Coke, lattes, or bottled water. I now bring my own in (got a Costco membership).

No more eating out. Spending less on groceries (fewer organic foods and specialty items). Tried Aldi's for the first time this week. So far I have only had the cheddar--it was ok.

I'm selling stuff we don't need--video games, furniture etc.

We're in an apartment and will move to a cheaper place when the lease is up.

High end grocery shopping and eating out

What are the first things you will cut down on if you lost your income?

Just some examples to get the discussion started:

Eating out
Buying lunch at the office
Starbucks
Organic, or more expensive groceries
Cable
Kids' activities
Entertainment- like going to the movies
Buying gifts for people
New clothes
Dry cleaning
Professional house cleaning

Would love to hear why/how you would cut down based on your list.

TIA!