The plants living in the pot sooner or later drain the earth, their roots grow, and it becomes crowded.
If you believe that your plant is almost not growing, despite regular top dressing, if the soil dries too quickly and the plant has to be watered often, and even more so if the roots sprouted through the drainage hole, then it is time to replant. To make sure of this exactly, take the plant out of the pot: if the earthen lump is densely braided by the roots, and the earth is almost invisible - yes, a transplant is necessary.
By the way, a plant bought in a store is also better to transplant into a larger pot, since the plants sold are planted in small pots to save space.
It is best to transplant plants in the spring so that the roots develop well before the onset of dormancy.
For transplanting, take the pot a little wider than the old one (2-3 cm) - transplanting into an oversized pot will do more harm than good.
Before planting, water the plant in at least an hour, preferably in a day.
Soak new clay pots before use in water overnight, thoroughly wash and use already used pots, then scald with boiling water.
Close the drainage hole in the clay pot with shards or pieces of broken brick, you can pour a layer of expanded clay. Sprinkle some earth on top.
Pick up a pot with a plant, turn it upside down and lightly tap its edges on the table, holding the plant. If it refuses to leave the pot, separate the roots from the walls of the pot with a knife. Remove, if any, old shards. Trim the rotten roots.
Set the plant on a layer of earth in a new pot and gradually fill the gaps between the walls of the pot and the roots with slightly moist earth. So that the earth evenly fills the free space without leaving voids, you can distribute the earth with a stick or gently tap the pot on the table.
Make sure that the plant sits in the soil no deeper than in the previous pot, and is located in the middle. Pour abundantly and put in a shaded place for about 1-2 weeks, if possible spray daily. You can cover the plant with plastic wrap or put a plastic bag on it.
Only after this can the plant be transferred to a permanent place and treated as usual. In the event that transplantation is impossible, for example, a plant grows in a very large pot or tub, you can replace it with the top layer of the earth (from 2 to 5 cm) fresh.