Plants don't like it

Why do the leaves of my peace lily turn brown on the tips? It gets plenty of water, and I'm sure I'm not over-watering.

Peace lily (Spathiphyllum) is hypersensitive to salts and fluoride. These chemicals can come from home water-softener systems that add salt to water, municipal water systems that add fluoride, or salt-based fertilizers. When a pot has no drainage holes, these chemicals build up enough to damage most potted plants. Repot your peace lily into a pot with holes. Use new soil or drench the soil with pure distilled (deionized) water to leach out the salts. In the future, water your peace lily with pure water.