First, how big are the brown tips, and how many? If there's only a few tiny (1/4" or less), that's just ordinary usage. If there are bigger tips (1/2" or more), and on most of the leaves, that's a sign that the soil is too wet, and the roots are in distress. You can easily trim the tips off - use scissors, and trim so that the natural shape of the leaf is preserved. However, if you don't allow the soil to dry more between waterings, you will eventually lose the plant. Test the soil in the bottom of the pot - it should be damp, but not too moist. (Of course, the other side of the coin is that you don't want the soil to get too dry. Some people routinely let peace lilies start to wilt before they water them, but I don't think that's a good practice either.)
The roots can talk to you through the leaf tips after you trim them off - if they're still too wet, the tips will come back, but if the soil has dried out enough, you won't see any more tips.