One of the biggest perks is that then both people get to share responsibility and both people also get to have some control over the prevention of pregnancy. There are other people who earnestly feel the world would come to an end and to whom pregnancy seems like the worst thing that could happen to them at a given time. Some folks feel fine without that personal control of their own, while it makes other people really uncomfortable. If, on the other hand, using two methods alleviates worries, it may be a real positive. This is something you can also talk with your partner about. Of course, you both also always have the option to spend more time before. There are a few reasons why some couples prefer using condoms, specifically, with another method to prevent pregnancy. How much you and your partner like using a given method and what kind of access you have to that method is often another factor. What any of those percents mean in the real world is this: For our readers at Scarleteen specifically, this is a pretty big deal since the age group with the highest rates of STIs are those in their teens and early 20s, with around one in every four people in that age group contracting an STI every year in the United States alone. You may find there are times in your life or relationships where you feel just fine using only one method, or this one method, and times when you feel a lot better backing your method up. If you do want that extra protection, either from pregnancy, STIs or both, and your boyfriend is having issues with erection when condoms are on right from the start, know that practice with condoms usually does make perfect. Other times, for whatever reason, it really is just the last thing we want to have happen. But if you know you use your pill as properly as possible, and have swung that for a year of use to know you can do so for a full year, if you average the typical use rate and the perfect use rate, you probably have a good sense of what your effectiveness is. How big or small a difference that seems to you, though, is going to be about you.