How much money do you need to be happy? Penelope Trunk wrote a couple years ago that “a wide body of research suggests the number is approximately $40,000 a year.”

That sounds like a reasonable number for decent shelter, food and other necessities, plus some wiggle room. (Of course, much depends on the size of your family and where you live.) The next question is: Why does that number sound ridiculously inadequate if you’re making a whole lot more than that?

It’s called “lifestyle inflation” or, as Andrew Chilton says at Retire at 40, “The more you earn, the more you spend.” Because many people are cutting back in anticipation of job loss or some other economic ill, now is the perfect time to get it under control.

Lifestyle inflation affects even the most budget-conscious among us. It happened to Alison at This Wasn’t in the Plan. Upon review, she realized her family’s income is up this year, but their savings don’t reflect that. “So, of course I started to make excuses,” she wrote. “But I couldn’t make these excuses account for much. Which means, we’ve slowly started to grow into our new income.”

“FMF” at Free Money Finance got a comment from a reader whose household income is $110,000. The reader said, “I find this is just ‘getting by’ and we have little debt and no children.”

We suggest that if you’re cutting back in anticipation of the worst, you consider carrying that new budget forward when the economy improves (and it will). How can you do that?

Among other things:

• Andrew suggests that you look at expenditures you started making after your pay went up. “If you didn’t have these things before, then you can probably still do without them now,” he writes.

• Canadian Dream: Free at 45 suggests having a separate savings account for those things that cause you to overspend. (In his case, it’s home renovation.) You can spend if you have the money saved, and have taken care of other savings obligations.