If your tap water is very hard, with a pH of 7.5 or higher (your municipality will be able to tell you), it would be wise repot your houseplants twice a year, in spring and early autumn, replacing almost all the potting mix each time. Hard water contains a lot of dissolved mineral salts, salts that are toxic to plant roots when they accumulate… which they will do very quickly in a pot where excess water doesn’t drain away, but remains in the saucer. By repotting twice a year and throwing the old potting mix into the compost, on the other hand, you’ll be cleaning the roots of contaminants, leading to much healthier growth from your plants.
If you can’t repot that often, consider leaching the mix every two months by letting water run through the soil and drain into the sink. Leaching likewise reduces the accumulation of mineral salts. You can find more information on leaching in the text Happy Houseplants Need Leaching.