You've settled down - maybe bought a house - and had a family. You deserve that new couch and the Fiji holiday right?
Nope - not if you have to borrow money to get them.
Experts say the biggest money mistakes people make in their 30s and 40s is borrowing for lifestyle reasons.
"If you borrow for a holiday or to buy nice clothes, sooner or later all you have is memories - and debt," according to financial adviser Simon Hassan.
"Better to borrow for things that grow in value over time [like a home] or help you improve your income [like education]."
Watch: Money Week - Do you worry about money - do you have a plan?
Hassan says people in their 30s should make repaying their mortgage a priority.
"Repaying personal debt is often the best investment option: in effect you earn the mortgage interest rate, with no tax to pay."
For those in their 40s he says trading up and extending your mortgage can be one of the biggest no-nos.
While rising house prices can make it feel like a smart move to sell up and move into a bigger house Hassan says few people actually get money back out of their house in retirement.
"Every dollar ploughed into your home (a lifestyle asset) is a dollar that is unlikely to help you fund your retirement."
Peter Lee, principle financial adviser at C2C Partners, calls lifestyle buying the gap between people's incomes and egos.
"They think everyone else has got XYZ...
"If we have got a house let's buy a new lounge suite."
Instead he recommends setting aside an hour a month to sit down and figure out the real priorities - what do you want out of life - what is really important?
Lee says those moving into their 40s will often find their earnings going up with one partner stepping back into the workforce as children get older.
The trouble is there is a tendency to spend all of it.
He says people want to reward themselves today without worrying about the future.
"Let's spend money because life is a bit easier for us."
Often people in their 40s will have thought about retirement but typically they are not serious about it, Lee says.
But he believes now is the time to put a plan in place to help set you up for the future.
"For people in their 40s it is really time to get serious about planning."
Biggest money mistakes to make in your 30s and 40s
• Buying consumable items like clothes and holidays on finance
• Up-sizing your house and mortgage
• Having no money plan in place for your future
• Failing to save if you income increases
Along with significant income people in their 40s are likely to have significant responsibilities so Lee says it is often a good time to revisit wills or set one up if you haven't got one and look at income protection insurance.
"Look at your situation - what could go wrong? Have you got a strategy in place."
Sharon Giblett, an adviser at Jigsaw Solutions, says it's easy to get lulled into a false sense of security in your 30s and 40s with the mortgage set and coming out each pay day.
But she urges people to take a closer look at their spending - consider how much interest you will be paying on that mortgage over a life-time and think about ways to cut that back.
Make sure you are getting the maximum tax credits through KiwiSaver by putting in at least $1042 a year and think about whether you are on track to save enough for the retirement you want.
"I think connecting some of those dots and looking at what the end outcome will be makes people more mindful."
We will put it to financial adviser Hannah McQueen as part of our live chat online on Friday at 12noon.