Your skis are an extremely important factor in the equipment used for skiing. As a beginner skier, it's always a good idea to rent skis until you get more confident on the slopes. Renting skis will allow you to get a better idea of what skis are best for you, and as you improve, you will be able to gauge how much time you want to spend on the slopes, and thus how much money you want to spend on your skis.
Ski boots are more important than you might think. After all, a pair of ill-fitting ski boots can easily ruin your ski day. Renting ski boots is fine when you're a beginner skier, but as you improve, buying your own pair of ski boots will make your ski day a lot more enjoyable.
Your bindings attach your boots to your skis. Bindings are set to skier classification, height, and weight. It is important that your bindings be set by a certified technician, because your bindings release you from your skis when you fall. If your bindings are set incorrectly, you could suffer a severe injury if your skis fail to release during a fall; or, on the other hand, you could find your bindings releasing too easily, and then you'll be falling more than necessary. Both of these can be easily avoided by getting your bindings set (and checked!) by a certified technician. This can be done at almost any ski store - and it is extremely important.
Ski poles are important to your balance, and they are extremely useful in helping to initiate your turns. Ski poles need to be light enough not to tire your arms (they shouldn't feel like a burden!), but strong and steady enough to hold up during your ski season - they need be used to turn, perhaps to break a fall, or to pole yourself along on flat terrain without breaking or bending. Ski poles can be rented at a ski resort, or they can be purchased at any ski store.
Ski accessories, such as ski goggles and a helmet, are just as important as your skis and boots. Why is that? Well, ski goggles protect your eyes from harsh precipitation and the bright glare of sun. Whether you're skiing through a blizzard, braving a day of high winds, or facing bright sun, then your ski goggles will come in extremely handy. As for a ski helmet, there should be no question about why it is so important. After all, a ski helmet will prevent injury or death during a fall or a crash, so wearing one keeps you that much safer on the slopes.