Another feature that was a standard for every single one of them: ugly old light switches. So I learned a trick, and I carried it with me (literally) to each consecutive apartment:
Change out the light switches! At least in the main room of studio apartments, it's a huge improvement to change from a dingy, old, painted-over switch to a fresh, new switch. On moving into my first apartment, I promptly went out and bought a Lutron paddle switch with a dimmer. It was a cinch to install. And I stored the ugly old one away until I moved out. Then, I switched everything back to the way I'd found it, moved to my new place, and promptly installed my switch again.
That switch moved with me to every apartment until I one day purchased a place with my husband. When we changed out all of the electrical in that apartment, my trusty and well-used paddle switch was installed in the bathroom and there it stayed (even after I moved away!). But it served me well over the years and was one simple, inexpensive, yet oft-used upgrade I'd advise anyone to try.