I always have offline maps downloaded on my Google Maps app. Aside from my home, I save my common driving routes and international regions I'm about to visit.

This serves two purposes: It keeps driving navigation active with a weak mobile signal and saves me from unnecessary data consumption while on an international roaming plan.

It recently got me thinking about how robust Google Maps' offline function really is.

Offline maps suggest you can do everything without a mobile data connection. To test this assumption, I tried using Google Maps fully offline for a week.

It got me to my destinations safely, but there were several restrictions along the way.

I gave offline Google Maps every advantage

No excuse to fail

I first made sure that the places I drove to were downloaded. I then turned off Wi-Fi and mobile data while keeping location services on.

Location services are essential in keeping my phone's GPS active. Without GPS, my phone would have no idea where I am.

I also viewed establishments near my destination, hoping to save them to my app's cache for offline viewing.

As expected, basic driving navigation worked well. I drove to my first location without problems.

The street names were intact, and my phone's GPS accurately tracked my car. Voice instructions for turn-by-turn driving directions didn't skip a beat.

I purposely took a minor detour, and Maps quickly put me back on track without requiring a U-turn.

Rerouting was surprisingly fast. It was faster during an offline trip than during an online attempt.

This may be because Maps relied on readily available offline data instead of searching for a solution via mobile data.

It helped that nearby businesses and landmarks were part of the downloaded route. I could double-check every instruction Maps gave me.

Still, there were downsides. The most obvious was not having real-time traffic updates. If there were a vehicular accident along the way, there'd be no way of knowing in advance.

Maps' weaknesses become glaring when it needs to think for me. Relying solely on offline maps works only for familiar places and driving routes.

Maps isn't an offline guide for pedestrians

Commuters can take a hike

Having online data is essential when driving around the city. Even if I'm familiar with the route, I can't predict sudden road closures.

This means offline ETA isn't accurate. Offline and online arrival times can vary by as much as an hour in the worst conditions.

In my testing, I saw differences by as little as five minutes because I knew the alternative routes and shortcuts in my area.

There's another issue: Downloaded maps don't work for walking and commuting directions.

This was an issue when I didn't plan in advance during the week. After parking my car, I didn't have turn-by-turn navigation while walking outside.

I could still use offline maps to plan my own walking route, but there were no optimized paths or stroller-friendly directions.

Select Wheelchair accessible under trip options when planning your walking route to avoid stairs and prioritize elevators.

I also tried searching for a bus route while offline, and nothing came up. I imagine this being a problem for tourists.

Tourists exploring a new country should be the target market for offline maps. Downloading in advance saves them from costly roaming bills and spotty mobile signals in rural areas.

They are less likely to drive around a foreign city and more likely to commute by train and bus.

By excluding pedestrians and commuters from offline maps, travelers would rely on Maps being connected online at all times abroad.

In my experience, offline maps work best when I already know where I'm going and worst when I'm exploring new regions.

I've already chosen Google Maps as a travel notebook for my next trip, but I won't depend on offline maps to guide me to new locations.

Offline maps save locations, not services

You must still prepare in advance

With these factors in mind, I had to reconfigure my planning for the remainder of the testing week.

I downloaded a larger area around my home to prevent accidentally exceeding the boundaries on longer drives, saved screenshots of establishments on my gallery app, and planned walking routes ahead of time.

By this point, I no longer saw the benefit of relying exclusively on offline maps. I could save a few megabytes on my data plan, but the consequences outweighed any advantage.

There are other minor issues with downloading maps, such as potentially high storage use and the need for periodic updates.

After completing the experiment, I saw no harm in continuing to use offline maps, but only as a backup.

Downloading maps gave me something more valuable than an offline version of the app. It supplied me with a fallback for the rare instances when online maps would disappear.

This week-long testing showed me how essential Google's online services are. Maps' intelligence comes from its ability to update itself on the fly.