I could probably eat the same thing several nights in a week if I lived by myself. In fact, when I did live by myself, and didn’t live in a dorm, I usually did make the same two or three dishes every night, and didn’t really care. Even now, if I am fortunate enough to be on my own for dinner for a week or more (which is very rare), I will usually just buy ingredients for two or three different meals, if only so I can cook a normal amount of food one night, and eat leftovers for a few nights afterwards.
However, in Real Life, I have a husband and two kids–all of whom have different eating preferences.
Mr. Kiminy prefers variety. While he doesn’t mind eating last night’s leftovers for lunch today, he doesn’t like to have the same food (or even the same main ingredient) several nights in a row, and he likes to try new foods.
Our 10yo son only really likes to eat a handful of dishes, and doesn’t mind repetition at all. In fact, when he was a toddler, he lived on macaroni and cheese with banana slices for lunch and dinner for a good solid year. He much prefers to eat foods that he is familiar with to food that he’s never seen before. He especially likes Italian pasta dishes–lasagna, spaghetti, tortellini, etc. If it has tomato sauce on it, he’ll eat it. 
Our 14yo daughter prefers to eat oriental food or pizza. Aside from pizza, she does not like Italian food. When I do serve spaghetti, she insists on having the sauce on the side, and she eats the noodles with a little soy sauce and chopsticks, so she can pretend it’s oriental instead. (She actually hasn’t used a fork at home for nearly a year, regardless of what we’re eating for dinner. She just uses chopsticks.)
In an effort to make sure that everyone eats (which is important when both children are drastically underweight), I do plan out menus every week. On Saturday night, I put together a menu for the week, based on suggestions from all family members, and avoiding anything we ate the previous week. On Sunday, I go to the store and buy all the provisions for that week’s menu.
Everyone I tell this to seems to think that I am hyperorganized to do this, but it’s literally the only way I can be sure to satisfy everyone at least some of the time. The BIG advantage for me is that when I get home in the evening, I already know what I am going to fix for dinner, AND I know that I have all of the required ingredients. The advantage for my husband is that he can be sure of not having the same meal show up on the table more than a couple of times a month. The advantage for my son is that I can be sure that we have Italian food at least once a week. The advantage for my daughter is that I can be sure that we will not have Italian more than once a week, and that we will have oriental at least once a week.
Fortunately, I do like to cook, and I have yet to meet a recipe I’m not willing to try. (There are, however, a few recipes that I have tried and failed at, though.)