It's difficult to answer that without a photo. Sometimes, depending on humidity levels, it can take longer for a plant to need watering again. That would be normal. But if it goes on for an extended period, then maybe the soil is too retentive, not enough light, or something is attacking the plant etc. Are the plants sitting next to each other? You can always remove the plant from the soil too and take a look at the roots and put it back in the pot if you're worried about roots.