Trimming your gift list may not be enough to help you stick to a holiday budget this year.
Presents are still the No. 1 category for spending, with shoppers expected to shell out $458 on them this year, according to Deloitte. That's up 9 percent from last year, and represents 35 percent of the typical shopper's overall $1,299 holiday budget.
Read MorePreparing for the holiday sales onslaught
But parties can be a stealth budget buster. Deloitte expects spending on "socializing away from home" to rise 15 percent, to an average $310. Costs to host a party are up 22 percent, to an average $194. Combined, that's almost 39 percent of your budget. (Solidly 50 percent, if you factor in the $144 in holiday spend on "nongift clothing"—because let's face it, you're not buying a holiday-themed sweater or sparkly party dress to hang out at home alone.)
Read More10 of the hottest toys for 2014
"The first thing I think about when I hear the dollars and cents is, life is short," said etiquette consultant Jodi R. R. Smith, author of "From Clueless to Class Act." "If you have the opportunity to celebrate the season with people you love, do it. Just don't go into debt doing it."
For a host, that entails scaling the event to your budget. Maybe that means menu swaps like punch rather than cocktails, or planning for a dessert party instead of hosting a full dinner. Guests should weigh the costs involved—travel? black-tie attire?—before committing, and explore tactics to cut that necessary spending. (Carpooling? Rent the Runway?)
Read MoreWhy sticking with your health plan could cost you
One cost saver for hosts to be careful of: potlucks, which shift some of the cost burden to guests. That's fine if a group you're part of decides to meet, and you subsequently offer your home, said Smith. (It's common enough at Thanksgiving, when a family would collectively decide who's hosting, and then, which relative is bringing the pie and which the cranberry sauce.) But inviting people to a party and then dictating each bring a specific dish or item can be offensive, she said.