Drawing from below
Is the plant in a pot with a hole for drainage? Then take a look under the pot. Do the roots grow out of the drainage hole? This is one of the clearest signs you can find: the plant definitely needs a larger size pot. Carefully loosen the roots from the bottom during repotting so as not to damage them too much.
Carrot surplus
The roots of a plant can also protrude from above. If that’s the case, throwing some dirt on top of it won’t help. You cannot keep doing this indefinitely. Time for a new pot.
Leaf discoloration
Yellow leaves or a large loss of leaves can also be a sign that the plant is ready for repotting. The houseplant can no longer get enough nutrition from the soil to stay strong and healthy. When repotting, provide the right potting soil with a supplement of houseplant food.