Also, I know that Lucy and Ricky celebrate their 13th wedding anniversary (in their closet lol) and their 15th anniversary (in Hollywood). Do they ever celebrate/acknowledge their 14th anniversary?
In Hollywood, it was supposed to be about three and a half to four months (Ricky mentions it's been three months in the Richard Widmark offering). I would think Europe was supposed to be about three, but that's a guess.
Lucy and Ricky celebrating their 15h wedding anniversary is a blooper, as they did celebrate their 13th anniversary only the year before (Ethel even mentions the party they planned for the couple).
Another goof: Ricky says in the Superman ep that they've been married 15 years (still??). It was now 1957!
I recall Ricky mentioning the "three months" timeline in the Richard Widmark episode. He does it when he explains why he won't take Lucy to the lunch he has scheduled with Widmark, but I didn't recall anyone stating how long they were in Hollywood.
As for the trip to Europe, I remember Fred mentioning at the cafe in Paris that they would be in Europe much longer than originally planned. I think it was in the Charles Boyer episode. It's made clear that the original tour of Europe was supposed to be three weeks, but I didn't recall anyone mentioning how long the actual trip was.
I was thinking maybe they glossed over "the 14th year," because the show also seems to advance Little Ricky's age pretty quickly. In the "Lucy Gets Homesick," episode, set in Italy, Lucy is upset at being away from Little Ricky on his THIRD birthday, but after they get home from Europe, in "Little Ricky's School Pageant," it's mentioned he's in Kindergarten, and, of course, he's older and more active in earlier episodes like "Little Ricky Learns to Play the Drums."
The glossing over the 14th anniversary was way before they "advanced" Little Ricky's age. His third birthday was correct (the Italian episode is in early '56, exactly three years after his '53 birth). However, he is suddenly FOUR AND A HALF by fall '56.
I don't think that even the writers were clear on the length of the Hollywood trip! When Lucy comes home with more clothes for the trip Ricky says that he is making ONE picture and they are going to be in Hollywood for ONE month. But it does turn out to be longer than that.
In the Hedda Hopper episode he is angry that he's not getting publicity. I think Ricky says something about being in Hollywood for a month and he isn't getting his name in the paper.