If you notice brown spots on your leaves, it might be because your plant is getting too much or too little water, or because the humidity is low or the temperature is too high. It could also be because of pests. I think the best thing you can do is try a few simple changes to how you care for it. First, try placing your plants away from bright, indirect sunlight. Then, cut them back in areas with brown spots. Finally, repot them every 1-2 years using well-draining potting mix.