UPDATE – Spirit apparently had second thoughts about the new size restrictions, and has elected to forego the changes reported in our article. According to a Spirit representative: “We had been preparing for a potential change in personal item sizes, however we decided a few weeks ago not to implement the change. While we always like to encourage passengers to carry less, we will continue to offer the largest personal size item of any ultra-low cost carrier.”

Spirit, widely derided by customers for its incessant nickel-and-diming, is at it again.

The latest ploy to separate flyers from their dollars is a niggling change to the maximum allowable dimensions for fee-free carry-on bags. But first, a quick primer on Spirit’s bag fees. Because Spirit does things differently.

As has become standard practice in the industry, Spirit charges extra for checked bags. Where Spirit differs from most other airlines is in also charging fees to carry one’s own bag onboard. That’s right: You’re charged for checking your bag, and you’re charged for carrying it on. You can’t win.

RELATED: Spirit Is Giving Away 1.6 Billion Miles. Should You Care?

But for carry-on bags, Spirit distinguishes between a personal item (a purse or shoulder bag, for instance) and a carry-on (a roll-aboard or the like, with a maximum size of 22x18x12 inches).

In the alternative universe of Spirit fees, personal items enjoy special status: They’re free to carry on. But, ever intent on maximizing fee revenue, Spirit is changing the rules, so fewer bags will qualify as personal items.

Beginning April 1, the maximum allowable size for a personal item will change from the current 16x14x12 to 17x13x8 inches. That’s a double-whammy for Spirit customers. First, the overall size is being reduced, from 42 inches (length + width + height) to 38 inches. And second, the new dimensions are less compatible with the profile of a typical shoulder bag. With a maximum width of 8 inches, many purses would fall outside the guidelines and be subject to a carry-on fee.

And those carry-on fees are hefty. For a test-booked Chicago-Dallas flight, the surcharge ranged from $26 if booked online to $100 if paid at the gate. That’s each way. For your slightly over-wide purse.

Naturally, Spirit provided no explanation for the change. That’s just what Spirit does.

Reader Reality Check

Would your personal item conform to Spirit’s new guideline, or would you be charged a carry-on fee?

After 20 years working in the travel industry, and almost that long writing about it, Tim Winship knows a thing or two about travel. Follow him on Twitter @twinship.

This article first appeared on SmarterTravel.com, where Tim Winship is Editor-at-Large.