I’ve stayed at over 500 hotels. There are 2 red flags I always notice before booking — and 3 that make me want to check out.

• As a travel writer, I've stayed at over 500 hotels around the world.
• I've gotten good at spotting red flags both before and after booking accommodations.
• Low-quality photos and neglected common areas are two non-negotiable red flags for me.

Long before I became a travel writer, I developed a love for hotels.

It didn't matter if it was a roadside motel or a five-star beach resort, the thrill of checking into somewhere new, flicking through unfamiliar TV channels, and sleeping in crisp sheets was a rush.

Now that I review hotels for a living, I've gotten pretty good at spotting red flags. Here are the top five things I look out for, both before booking and after I've arrived.

Low-quality photos and vague property descriptions on a hotel's website

If the photos available online are grainy, dark, outdated, or irrelevant to the space, I won't be booking a room. After all, first impressions are important when choosing a place to stay.

Of course, some accommodations (like new or very small ones), might have a good reason for not having high-quality images. So, if I'm concerned, I like to reach out to the hotel to ask for up-to-date photos or videos.

Likewise, vague property descriptions online are a red flag for me, too. A listing should clearly tell you what to expect from the property and what's nearby.

Consistently bad recent reviews

It doesn't take an expert to understand that bad reviews are a warning sign.

However, I've noticed that some booking platforms seem to highlight the "most relevant" reviews, which, in my experience, tend to skew positive or may be dated. Instead, I always sort by the "most recent" reviews and scan the last 10 or more to spot patterns.

I like to look for repeated mentions of things like dampness, noise issues, hard beds, or poor cleanliness.

When in doubt, I like to cross-check reviews against other booking platforms.

Neglected common areas

If a hotel's shared spaces look shabby, it's usually a good indicator to me that the rooms won't be much better.

That's why my alarm bells ring if I notice musty smells, peeling wallpaper, stained carpets, or broken furniture in a common area, such as a lobby or stairwell.

Dirty rooms

No matter the price point, I think a clean room is the bare minimum any guest should expect, whether you're staying in a $10 hostel or a $1,700-a-night boutique hotel.

Stained bedding, yellowed mattresses with no protectors, hair in the sink, dusty shelves, and dead insects on a mosquito net are all immediate deal-breakers for me.

Uncomfortable mattresses and low-quality bedding

Finally, I think the biggest hotel red flag is an uncomfortable bed setup.

Generally, you're staying at a hotel to get a good night's sleep. So, to me, there's no good reason the bed should be hard, have springs that poke into your back, or have lumpy pillows.