I've stayed in 13 countries for free by house sitting. Here are 3 tips for starting your own house-sitting journey.

Marius Schmidt has traveled the world and never paid for a room by house sitting. He said asking for reviews was crucial to building his business.

• In 2017, Marius Schmidt sold all his stuff and left Münster, Germany, to travel the world full time.
• Schmidt used to stay in Airbnbs, but discovered house sitting in 2020 and now his stays are free.
• He detailed how travelers can get started, like asking clients for reviews to boost trustworthiness.

This as-told-to essay is based on a conversation with Marius Schmidt, 34, about what he's learned as a house sitter over the past two years. Schmidt uses sites including TrustedHousesitters and Nomador to find stays throughout the world, though those following in his footsteps should be aware of visa rules in each country they enter. The following has been edited for length and clarity.

I am originally from Münster, Germany, a university town.

In November 2017, I started traveling full time. I sold all my stuff at home and traveled with only two backpacks. Since then I've been traveling all the time — I don't have a home.

Then COVID-19 hit, and I went back to Germany.

My ex-girlfriend taught me about this thing where people house sit for other people. At first I didn't understand it. I thought, "How does that even work?"

When COVID began to relax in Europe, I thought maybe I'll try house sitting out and see if I can actually do it myself. And that's how it started.

I've been house sitting now for 2½ years. I've done 27 sits in places like Dubai, Spain, Portugal, Switzerland, Germany, and Bulgaria.

Normally I go out and explore everyday. This life is no different than when I traveled with Airbnb.

It's only housing for free. That's always the deal. Sometimes the host says you can have all of the food or sometimes a car because they don't take it with them. But there's normally no payment involved.

Ninety-nine percent of the time there are animals. There's rare occasions where it's a big compound, so there's a lot of work for the garden and pool, but it's normally always with animals.

Tip 1: Be selective

From the start, I would be very selective. Don't go for everything.

Basically, make the choices of where you want to visit and how long you want to visit for, which takes it down to only a few houses, normally.

Being selective makes your experience better because you will like the house at the end more if it's exactly what you're looking for.

It's a bit harder at the beginning because you want to get reviews. In the beginning I started doing a lot of short sits, like a week or a few days, to get my reviews up.

Once you have the reviews, then it's easier to get the longer-term houses. I mostly stay long term, or not less than a month — two to three months, preferably.

Tip 2: Treat it like a job application

One thing that you can do is post an Airbnb profile on your house-sitter page. I already had 40-something reviews on Airbnb, which helps a lot. It shows you're a more trustworthy person. You can also put in a nice LinkedIn profile.

Otherwise it's important to be very open about everything: what you do, what you would provide to them, and what you did in the past — like your experiences with animals and that kind of stuff. Try to mention as much as possible to make yourself look credible.

Your profile is like a CV that you make for yourself, basically.

Normally, you do a video chat with the hosts beforehand, and it's good to ask questions and get the feeling of the house, and how it actually is.

I've heard from a few other house sitters that sometimes it is really messy or not a very nice house.

Only recently have I had a bad experience. There was a person that drove to work everyday. She still was living there, but needed someone to stay over during the day.

I don't do that anymore. They need to go and I need to be alone there. That was a key lesson.

Ask a lot of questions in regards to what is allowed and what is not allowed. And if you don't feel right about the host, don't be greedy and take it. Sometimes I've felt weird about the hosts and then decided not to take it.

And what a lot of people are not doing is asking for reviews at the end. When you're finished, after one or two days, say "I would appreciate a review from you." That's important.

Tip 3: Constant communication is key

For the host, I try to do the best I can to make them feel very taken care of when they're gone. There's a lot of communication and I also try to leave the house better than it was before.

If you see something that can be fixed, fix it. If something can be cleaned, clean it.

Every weekend I try to send a video of the whole home so that they can see everything is alright. Then normally I do daily videos and photos of the cat whenever I play with it.

I only choose sits with cats because it's so easy compared to dogs or anything else.

With cats, you give them food in the morning, give them some water, and play with them in between a bit. That's it. Dogs are more needy. You actually need to go out two to three times at specific times. You don't have the freedom to travel freely while still being a house sitter. With cats you can go out whenever you want and do stuff.