I've mentioned in the past that we don't have any secondary sets of sheets or duvet covers in our home. We have 3 beds total, Our queen wall bed, and the two twin bunk beds but we only keep enough sheets and duvets for the beds we have.
When we looked at our closets we analyzed any excess. Bedding takes up a lot of space. If we stored a set of twin bedding as well as queen bedding we would lose 1-2 shelves of our bathroom linen closet. Considering storage is highly valued in our small home, the amount of use we got from our spare bedding did not justify the space it occupied. As an experiment I tried washing and drying our bedding in the same day. On a sunny day, hung on our patio, the sheets dry in time for bedtime. On a cold winter's day we have to use our dryer to dry everything in time. Beds remain un-made for the day and are remade before bedtime. We are lucky to have a stackable washer and dryer in our front hallway.
I have been asked what happens if there is an accident? We have soft mattress protectors on the kid's beds that in a pinch they can sleep on. Mae still wears pull ups at night (she's 2) and Theo just wears underwear and isn't prone to accidents (I know every kid is different and we may need to adjust if Mae ends up having a smaller bladder than Theo when it's time to lose the pull-ups). We also store beach towels and blankets in the master closet that can be used as extra blankets if for some reason the sheets didn't dry in time. Likewise our merino wool blanket in our living room can be used as an extra layer in the winter months or as the only layer if the bedding didn't dry in time.
On the rare occasion we have guests sleep on our couch we bring up the bedding from our camper van for them to use. It is slightly inconvenient to not have spare bedding in the home but I think it's a great solution for a small space. Our bedding may wear faster but quality bedding should be able to handle the wear and tear (our bedding is linen from Last Light Collection, and the kids' is from Ikea).
What other expected things do you not have in your small space? Some others for us are single use kitchen tools, an iron and ironing board.