All houseplants eventually outgrow their pots. At some point, your indoor plants need a bigger pot that can hold more soil to give their roots room to grow. Let a plant get root-bound, and it will fail to thrive. But how often should you repot your houseplants? It depends on several factors, including the type of houseplant and the amount of light and water it gets. Here’s how to tell when you should repot, according to indoor plant experts.

When to Repot Houseplants

In general, repotting houseplants every year or two can be beneficial, but some plants can go much longer in the same pot. “There isn’t a strict timeline for repotting,” says Paris Lalicata. “There are so many variables as to how fast a plant will outgrow a pot. I have a pencil cactus that’s been in the same pot for 10 years.”

Slow-growing plants that thrive in poor soil, such as succulents and cacti, can go for years between repottings, while fast-growing plants need nutrient-rich soil. Philodendrons and pothos may need to be repotted annually. The key to knowing when a houseplant has outgrown its pot is to recognize the signs that it needs more space and fresh soil. Here’s what to look for.

1. Roots Growing Out Drainage Holes

Roots poking out of the drainage holes at the bottom of the pot is a sure sign your plant needs a bigger pot. “Those roots are searching for nutrients and water they cannot find in the pot,” Lalicata says.

Sometimes, roots become so crowded that they will be visible at the top of the soil in the container. “I’ve even seen plants push themselves up out of the pot with their roots because they needed more space,” Lalicata says. Generally, a plant whose roots are poking out will be completely root-bound. A larger pot and fresh soil is overdue.

2. Soil Dries Out Fast

“If your plant dries out quickly between waterings, in just a day or two, you may need to repot the plant,” says Jason Paluzzi of BWH Plant Co. “It is drying out fast because there is very little organic matter remaining in the soil to hold moisture.”

A more obvious sign your plant needs repotting is when you water the plant and the water runs straight through to the dish below. The water does not remain in the pot because there are more roots in the pot than soil or because the worn-out soil can no longer hold water.

3. Plant Keeps Falling Over

If a plant is a lot bigger than its pot, there’s a chance it’s root-bound and needs a larger pot. There’s also a good chance the root-bound plant is tipping over because it’s top-heavy.

Ideally, a container should be as wide as the plant. “Tall plants especially need a bigger pot to stabilize them,” says Carli Paluzzi. “They need the weight of the soil to offset the height of the plant.” A 4-foot-tall fiddle leaf fig in a quart-sized pot is probably root-bound and probably also falling over because of gravity.

4. Compressed Soil

Old, tired potting soil will get compacted. There will be less soil in the pot, and you may think your soil has disappeared. What has happened, though, is that its organic matter has decayed and been absorbed by the plant in the process of turning the soil’s nutrients into new roots, leaves, and stems.

Watering also displaces the air in the soil and causes the soil to compact. “All of this will make your soil shrink in the pot,” Lalicata says. This means your soil is worn out and needs to be replaced with fresh, nutrient-rich soil, she adds.

5. Plant Looks Sickly

A plant that is not putting out much growth and has stunted or yellowing leaves is another possible indicator that it needs to be repotted. The plant could be root-bound, or its soil could be worn out and depleted of nutrients and organic matter that holds water in the soil.

“Soil is food for a plant in a container,” says Carli Paluzzi. “If your soil gets worn out or your plant outgrows a pot, the plant slowly starves to death.”

Gently easing the plant out of its container quickly reveals the cause of the problem. However, if the soil does not show any compaction and the plant is not root-bound, the unhealthy appearance has other causes such as root rot from overwatering. Repotting into fresh potting soil may help save a plant in this situation too.