Signs from below
Is the plant in a pot with a hole for drainage? Then take a look under the pot. Are the roots growing out of the drainage hole? This is one of the clearest signs you can find: the plant is definitely ready for a larger size pot. Carefully loosen the roots from the bottom during repotting so they don’t get damaged too much.
Root excess
A plant’s roots can also start to protrude from above. If this is the case, simply throwing some soil on top will not help. You can’t keep doing this indefinitely. So it is really 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, make sure you use the right potting soil with a supplement of houseplant nutrition.