@Stephanie great topic. Curious to hear what others say.
For us it was using easy clean fabrics and rugs. We are pet friendly so we knew that accidents might be possible. Thus we bought a big vintage leather sofa (a Harrods original that probably cost loads new but we got for a song), throw and area rugs that are stain resistant and replaced some flooring in our half finished laundry room with vintage look linoleum which is easy clean.
We didn't cheap out on mattresses but went with memory foam as we have very steep stairs and a traditional mattress with springs would have been a bear to get up there. We purchased the one with the best reviews that we could afford.
I actually had a lot of really cool original artwork in the space (we collect art) but I took it all down and replaced it with framed paintings of lower value and canvas prints. We didn't want to lose a piece worth a lot of money.
As far as furnishings in general, we went mid-level to inexpensive. We looked for durable, good looking to photograph well and easy to replace if destroyed. We spent more money on towels and did mid range bedding (bamboo, eco friendly and soft.) There were a few fun splurge pieces to elevate the feel of the space, but nothing I would cry over if destroyed.
Our biggest learning curve was the bed itself. We have had some larger guests who bent a metal bedframe upstairs. Guests that moved this bed also scratced the floor. This year we replaced with a wood bed rated to hold a lot of weight (its SOLID) and a bigger rug to protect the floor. So far no issues.