Hey all, I barely passed the December 2022 N3 and last month, I went to Japan for the first time and spent two weeks there.
Overall, I was both disappointed and pleased with how far the N3 got me (note I'm talking purely about my skill level -- at no point did I ever show anyone in Japan my N3 certificate lol).
On the one hand, some might say that N3 is enough for anime and conversations with normal people. As someone with a 31/60 on the listening section, this is categorically not true. I never got the chance to, nor do I likely have the ability to, hold a long everyday conversation with anyone in Japan. It's not like I was surprised at my lack of skill by the time I was on the ground in Japan and talking to people, but I did expect to have been able to do so by the time I got an N3 back when I first started studying. So I am a bit sad that that expectation was off.
On the other hand, wow does real immersion make a huge, gigantic difference. When I first landed I had to ask people to repeat themselves slowly two or three times for me to get what they said, and people would often switch to English before I put together what Japanese words (that I already knew) actually corresponded to the sounds I was hearing when they were speaking Japanese earlier. But by the end of the first week, my conversation skill was enough for dining in restaurants, shopping in malls, speaking to hotel staff, and small talk with tour guides 100% in Japanese. It was incredible how comfortable I felt talking about non-trivial upgrade options or specific observation site locations, and it was also incredible how much nicer people treated me when I was speaking Japanese with them vs when my wife would talk first in English. It was absolutely 100% worth it for me to get to this level of skill, and it really made me feel like my work has finally paid off.
To conclude, if you're like me and you grinded almost nothing but Anki all the way to around N3 level, you probably have the same mix of okay vocab/grammar but extremely shitty listening comprehension. If so, I highly recommend greatly increasing the amount of listening practice you do on a daily basis. I'm still not sure what's the best way to study that, but I definitely could have used more of it before my trip. But at the same time, don't despair if you're going on a trip without that. You'll be fine -- trust your subconscious brain and enjoy the huge comprehension gains!
Tips: check tabelog (Japanese yelp) for restaurant recs. They're real harsh on reviews there -- if a restaurant is rated above 3.5 you know you're in for a good meal, and finding one above 4 is very rare. Many of the "best meals of my life" I talked about were from restaurants rated about 3.8 or so on tabelog (the 4+ ones were too expensive or too hard to book).
If you know some Japanese, calling restaurants to reserve will sometimes let you eat somewhere that you wouldn't have been able to otherwise. Many restaurants in Japan are very small and/or reservation only without an online option, so being able to reserve in Japanese is a huge advantage. I used Skype to get a Japanese number to reserve with
In terms of Japanese language, like the other guy said prioritize your katakana reading ability. It's by far the most useful bang for buck you could get in terms of language ability.
I did a lot of research before I went so there wasn't much that we didn't expect, but one big thing was how gruelling the jet lag is after the 13 hour flight. We definitely didn't schedule enough restful days upon landing, and next time we'll be sure to take it easy when we first arrive. Best of luck planning your trip!