Being a renter does not need to involve improvement paralysis.
You want to enjoy that house even thou it is not technically yours, but it should not feel like a waiting room where you count the days until next apartment.
You might live there just for a year or longer, either way, there are things you can do to make yourself feel more relaxed, comfortable and not spending that much money in doing so.
Of course, significant improvements or renovations require approval from the landlord. Be sure of what is written in your contract, and perhaps it is stating that whatever upgrades and changes you do in the apartment, once when you leave the apartment you need to put it back in the original state. Also, that gives you the idea of your possibilities and limits. Make sure to have that in your contract, it is an excellent way to make each side accountable and it allows you to execute specific changes without feeling that you are breaking the law.
Whatever your case is, there are a few things that you can do.
Whatever you buy for the house, it goes with you to the next one. With that rule, you are preventing yourself from buying items whenever you are moving; you are investing in those items with durability on your mind, and your style.
You will upgrade, and you take it with you, and when the time comes for you to leave, you will reinstall the items you initially found in the house, so yes keep those safe and in good condition as well.
You should know that some hardware items need to satisfy dimension standards, meaning they will probably fit in the other house as well.
A straightforward upgrade is kitchen and bathroom faucet, and a showerhead. It works miracles when your kitchen or bathroom is annoying, and you need that one essential piece to make space glow and look different.
Another thing is handles and pulls for cabinets, either one in the bathroom, sleeping room, kitchen etc. Nowadays design of these items allows you to have a diversity of choices and fantasise about the possibilities and again its standard measures will enable you to reinstall them when moving to next home.
While we are in the kitchen and storage section, some companies produce cabinet fronts for IKEA cabinet structure. In case that is what you have found in your new rented apartment: buy the structure from Ikea and design it with new fronts and handles. The options are something completely different than your usual IKEA.
Light fixtures are usually the best item to upgrade the entire house, uplift the home and bring the mood. If you have found a lighting fixture in the house already, take them down and store them safely, install your choice and enjoy. Considering that you might change the fixtures in every room of the new space and that you will probably splurge, but know that whatever you buy goes with you and gives you the control over the mood and atmosphere in your new home, and that is important.
Light switches and power outlets are plastic and ugly? Get something that might give an accent to your home and allow you to dim the lights if that is your preference.
Some of the other simple upgrades you can do is painting the walls, and of course, this is something that you cannot take with you, but it does wonders for you and your space so I would not skip that part. You would paint the walls back in white anyhow when you leave so why to play safe. Brainstorm, make a mood-board, find out what you like and what fits the space depending on the natural light resource. Although if this is just a super temporary place to stay, one year max, and you cannot afford many renovations, having neutral paint colours will make it easier for you to create a polished and pulled up together look using what you got.
Of course, furniture is a part of that group you would take with you. A sofa is something like a central piece where everyone will gather around and enjoy Sunday brunch and evenings among friends.
A rug is sometimes like a frame for the room (and it does cover the possibly ugly floor you cannot get rid of). It makes the room warmer, and it isolates the sound between you and your neighbour.
Mirrors, in cases of the small and dark apartments, create the sensation of bigger space and extend that small amount of natural light that enters the home. Otherwise, even in average sizes of the house, mirrors are an excellent decorative addition.
Except in mine, I own only a make-up mirror. I came to that situation unwillingly, and it stayed like that since wanting and needing a mirror moved somewhere to the back of my head, to be forgotten. I am at a year five without it.
Yes, I do get dressed without a mirror. It is not science if you know yourself, your body and wardrobe.
I will add the curtains as a decorative item that can uplift your home, but I will be honest I am not a big fan of any curtains, that might change, but that is my choice for my house. I love the sun and natural daylight.
Buy plants, lots of them. Grow mini avocado trees, make a jungle. There is no better way to feel at a comfortable home and far away in a tropical place at the same time.
Whatever you purchase, think about it as the investment for the next home, it is financially hard on your wallet to buy new items for a new home every time you move, even if you opt for the cheapest things. If your budget is small, create a minimalistic yet cosy and safe harbour and be patient while you are working on upgrading your life quality. Don´t be in a hurry.