I've been on 105-day cruises, but this 13-day one was the toughest. Its itinerary had a major flaw I'll avoid on future trips.

• I went on a 13-day cruise aboard Norwegian Cruise Line's Jewel that left little time for relaxation.
• We only spent two days at sea which left me missing out on the ship's perks and feeling exhausted.

As a frequent cruiser, I've been on a few port-heavy itineraries, but none hit me quite as hard as Norwegian Cruise Line's 13-day Asia cruise last fall.

The cruise departed from Keelung in northeast Taiwan and stopped at 10 ports in six Asian countries, including the Philippines, Malaysia, and Brunei — places I hadn't been to and definitely didn't want to skip.

I knew the itinerary was packed, but I didn't realize how intense it would feel with only two of the 13 days spent at sea. The ambitious schedule left me, a seasoned cruiser, exhausted.

Here's why this itinerary was tough for me and why they're not ideal for every type of traveler.

I felt pressure to enjoy every minute in port

With only one day in each port, I didn't want to skip going ashore for fear of missing out.

I tried to maximize my time by researching each destination and carefully planning my schedule before the cruise. Still, I felt tired from long days exploring new places in the heat day after day.

Sometimes, I wanted to sleep in, take an afternoon nap, or return to the ship early — things I enjoy doing on sea days. Instead, I woke up early for either a cruise-arranged excursion or my own exploration and then returned to the ship six to nine hours later.

This gave me about four to six hours to eat dinner, go to the gym, and then see a show, relax in the thermal suite, or explore the ship before getting prepared for the next day.

Because I have severe FOMO, early every hour of my day was allocated to doing something, just like when I'm not traveling. I didn't end up relaxing or resting even though I was on vacation.

Plus, I didn't get to fully enjoy the ship and its amenities

With a self-imposed regimented schedule, I felt like I was on a hop-on, hop-off tour of Asia and constantly in go-go-go mode.

When the first sea day finally came more than halfway through the cruise, I was too tired to explore the ship and participate in onboard activities like trivia, lounge by the pool, or indulge in spa treatments.

Worse, the Norwegian Jewel isn't even very large and I still couldn't efficiently experience its amenities and offerings. The Jewel is one of Norwegian's smaller ships at 965-feet and I still only ate in half of its 11 restaurants and drank at a handful of its 13 bars.

First-time cruisers may be overwhelmed by such a port-heavy cruise

My trip was packed with excitement, but I disembarked feeling exhausted and like I needed a vacation from my vacation.

Ultimately, I think adding one or two sea days to the itinerary would've improved the experience and given me space to relax.

Although it's nice to check off a ton of destinations in one sailing, itineraries with more sea days allow travelers to experience all the amenities ships have to offer without having to sacrifice time at a port.

Plus, multiple sea days in a row can provide beginner or first-time cruisers insight into whether they like them. This can be useful to anyone contemplating trans-Atlantic and trans-Pacific crossings that can have seven or more sea days in a row.

That said, cruises with port-heavy itineraries and hardly any sea days could be a good choice for people who don't like cruising but love travel since more time may be spent on land than at sea.

For me, after going on more than 25 cruises — including a 105-day sailing — I've found the best cadence of busy port days to relaxing sea days is a ratio of 2:1. I'll definitely be looking for that ratio when booking future travels.