Definitely. Especially the oil and the radiator. This is particularly important if you have an older vehicle, which is more susceptible to problems. I try to emphasize this point to my 18-year-old daughter who now has a car at college. I can't be there to be checking it all the time. I had problems with my own vehicle, a 7-year-old Jeep Wrangler, last winter. I was losing antifreeze/water. First, it was the water pump. Then it was discovered the head was warped and antifreeze was going into the engine. If I hadn't been watching the situation closely, I would have been buying a new engine instead of paying for relatively minor repairs. On most vehicles, you have a reserve tank for the radiator, and you can tell by looking at that if you are losing fluid. The windshield washer fluid is important, but it's not like you are going to wreck your engine if you run out.