Vertical space that respects a deposit and a small floor plan
Two students and one cat in a single flat usually means three constraints at once: little spare floor, a landlord who will not love a wall of screws, and a cat who still needs somewhere higher than the sofa arm. The answer is to build upward using furniture that already exists. A tall bookcase becomes the tower — clear alternate shelves in a zig-zag, leave the books on the others, and put a folded blanket on the top. A chest of drawers or the wardrobe in the bedroom extends the circuit, so the cat gains a route that spans both rooms without a single new piece of bulky furniture.
The one purchase that earns its footprint
If anything is bought, make it a tall scratching post that braces between floor and ceiling with a tension fitting, or a heavy-based post that cannot be tipped during an enthusiastic climb. Place it beside the bookcase so the post is the on-ramp to the shelves, not an isolated pole the cat ignores. A suction or clamp-fixed window perch at the end of the route gives the reward every cat actually climbs for: a warm lookout. Test window fixings with a firm pull before trusting them, and position the perch over a sofa or bed rather than a hard floor while the cat is still learning its bounce.
Rules that stop the route becoming a shelf for human clutter
In a student flat, any flat surface attracts clutter within days — mugs, chargers, laundry piles and essay printouts will colonise the cat's landings unless both of you agree they are reserved. A landing blocked by a laptop forces the cat onto the desk instead, which is how keyboards get slept on. Keep the cleared shelves cleared, move the blanket bed back when it migrates, and never use the top of the bookcase for storage overflow. The cat's willingness to use the circuit depends entirely on finding it exactly as she left it.
Two timetables, one maintenance habit
Student life runs in bursts — deadlines, part-time shifts, trips home — and cat furniture quietly degrades in the gaps: the tension post loosens, the window perch pads slip, the blanket needs washing. Split the upkeep explicitly rather than assuming the cat's owner does it all; one of you checks fixings and re-tightens the post, the other washes bedding and vacuums the shelves. Short, named jobs survive exam season far better than a vague promise to keep an eye on things, and the cat keeps a safe route through the busiest weeks of term.
Marking the jobs done where both of you can see them
A rota scribbled on a whiteboard fades; a shared task list does not. Recording the post check, the perch clean and the blanket wash as recurring duties means either student can see at a glance what was done and when, and nothing depends on catching each other in the kitchen. KinsLe Care Teams lets the two of you assign those vertical-space chores for the cat between you, with each finished job marked and timestamped, so the flat's smallest resident keeps her high route in good order on a student schedule.