Since they started sharing their ideas on social media, the twins have become online darlings of decor - a place where their fans can go to share their decorating tips and techniques every day.
"We feel like we know them," Lancia says about their followers.
"Yeah," agreed Kammerer. "It's like a huge family."
While they don't have any formal training or background in design, the whole twin thing has been forever.
"We're really pros at that," laughs Kammerer. And while they may disagree on who is bossier, they do agree on breaking the "rules of decorating" and having a blast while doing it.
"We don't make rules," said Lancia. "We just follow our own instincts. It's my aesthetic! I don't care if it's from four different genres, five different time frames - it's just more about a visual love."
While visiting Lancia's home in Sammamish - decked to the BRIM with holiday spirit - we took the opportunity to ask The Design Twins for their tips on dealing with some common decorating dilemmas. First up - the what to do with the dining room table.
"The table setting is about layers," said Kammerer. "You've got your charger - so simple, easy. Let's break it up with a tartan napkin, so you've got just a little bit peeking out. A little bit of green, a simple little wreath. This is natural elements and then the pine cone."
"It's not about food, it's about décor," Lancia chimes in. "We don't have any idea where the food's going. But that's okay."
Another things folks have a tough time with is where to place the ornaments on the Christmas tree.
"Don't let the children help," Lancia jokes. "Do it in triangles - triangles or diamond shapes."
Lancia loves to use old book pages in her festive displays. This time, they're forming a circular frame around an oversized wooden clock.
"This is décor as art," she explains. "I am obsessed with books and pages so there's this theme all the way around to do with old books, without destroying too many. I took some pages from these vintage books and just created a bit of a visual frame that feels organic and fun and isn't just about the clock."
The twins say when it comes to decorating, start small and don't take it too seriously.
"Throw the pillow on there. See if you like it and if you don't, throw it off," said Kammerer. "But it's really not rocket science."
"Have fun!" Lancia adds. "We always tell people have fun happy decorating, and we mean it.