If you're finding that the tips of the leaves on your houseplants are turning brown it could be that you're not watering well or the air is too dry. Here's how to check to make sure it's not a watering problem: pick up your plant (where possible) and place your hand on the top of the pot, now turn the plant over so that the soil (and top of the pot) are now resting on your palm. With your free hand lift the pot off and examine the soil. Is it bone dry? Or is it still moist? What do the roots look like?
If the soil is moist and you know you're watering well then the reason for the unhealthy looking plant leaves is that the air around your plant is too dry. Keep your plant away from heating vents and increase humidity around your plants by making humidity trays out of things around your house. Add a humidifier to your house or find some frugal methods of increasing humidity in your home during the winter.
If the root ball was dry then consider giving your plant more water along with increasing the ambient humidity. When you checked your plant if the root ball was all roots and you could hardly see any soil it's probably time to pot up your houseplant into a larger pot.
Other causes for browning tips could be related to the fertilizer you're using and how much. Salt buildups causes brown tips on some houseplants and some houseplants are sensitive to the chemicals we add to our drinking supply. Some ways I get around this are fertilizing properly and watering with bottled water when possible. Around the house there are always half empty bottles of water so I store them and use them for my plants. Sometimes I'll collect rain water or I'll melt snow indoors and use the water on my houseplants.