I spent a month in Turkey with friends. Our trip was great, but would’ve been better if we’d avoided these 5 mistakes.

Istanbul is the biggest city I’ve ever visited — it’s so large that it actually hosts two international airports.

Istanbul Airport (IST) is on the European side of the city and Sabiha Gökçen International Airport (SAW) is on the Asian side. It can take about two hours to get from one airport to the other by bus.

My friends and I all flew into IST, but some of our group booked domestic flights out of SAW the following morning without realizing it was a different airport in Istanbul.

We all made our flights, but we had to split up into different hotels during our Istanbul layover, one near IST and one near SAW.

Since I arrived in Istanbul was after business hours, I figured my best option was to exchange US dollars for liras at the airport despite the poor exchange rate.

After all, it seemed like a bad idea to enter a new city without any cash.

However, I regretted my decision as soon as I left the airport and found that many exchange counters in the city were open late — and had better rates. It was also easy to find ATMs throughout the trip.

After that first money mishap at the airport, I got all my liras from Halkbank ATMs, which didn’t charge me fees.

Turkish tea, or “çay” (pronounced like “chai”), is a popular drink in Turkey, and sharing tea is an important part of Turkish culture.

For my first few days in Turkey, I accepted tea whenever it was offered. It was inexpensive and delicious, and I was eager to participate in local rituals.

I was offered the tea at restaurants, shops, and even at the dentist’s office (I was there for a bit of medical tourism).

What I didn’t realize at first, though, is that çay is pretty caffeinated.

Although it varies depending on the strength of the brew, an average cup can contain over 40 milligrams of caffeine — about half of the caffeine in a standard cup of coffee.

Once I registered how much caffeine I’d been drinking throughout the day, I understood why my jet lag was so much worse than usual.

I loved browsing the Grand Bazaar in Istanbul, but I wish I hadn’t bought souvenirs there.

The famed Turkish market and its mazes of different stalls felt overwhelming in a good way. I was captivated by the endless colors of Turkish textiles, the rich smells of spices and teas, and the banter of shopkeepers trying to entice us into their stores.

I bought a few things at the Grand Bazaar, but I wish I’d held out on shopping until the next day, when we took the ferry to Kadikoy, a neighborhood on the other side of the Bosphorus.

I found many of the same wares in Kadikoy that I’d seen at the Grand Bazaar, oftentimes for almost a tenth of the price.

Turkey is famous for its cuisine, and eating my weight in baklava was a highlight of my monthlong trip. When it was time to return home, I wanted to bring back some of my favorite Turkish delicacies as Christmas gifts for my family.

Shops in Istanbul made it easy to bring home food, with some sellers even offering to vacuum-seal items like baklava and olives.

Most of my culinary delights made it home, but I was heartbroken and slightly embarrassed when my giant bag of dried persimmons was confiscated upon my return to the US.

As it turns out, most dried fruits and vegetables from other countries aren’t allowed to be brought into the country. I should’ve checked the guidelines before shopping.