There may be several reasons why your plant needs to be transplanted. Each plant has very specific needs, but in general, they all give you signs of what they need, and transplanting is no exception.
When to transplant a plant
For example, when you notice that your plant is too big for the pot it is in, it is a sign that it needs to be moved to a larger pot and, before it starts showing other signs, you should move it. The same happens when the roots start to come out of the drainage holes of the production pot. This indicates that the plant needs more space to grow and that, therefore, you should move it to a pot where it can grow with more space.
Another sign that you should not ignore is the quality of the soil. When you notice that the soil where your plant is growing is becoming very compact and dry, or when you notice that the water is not penetrating the soil and is running down the sides, it is a sign that your plant needs to be transplanted and that the soil where it is growing is no longer of good quality and is not giving it what it needs. You should keep an eye on your plant and observe it closely so that you do not miss any signs.
How to prepare the plant and pot for transplanting
When transplanting, there are some important things you need to know. The size of the pot, the quality of the soil, the drainage and the preparation of the plant before transplanting are all important steps that you should not overlook. The new pot should be between 5 and 7 centimeters larger than the pot where the plant was, to ensure that there is enough space for your plant to grow healthily.
Drainage holes also play a very important role, as they are responsible for draining any excess water that your plant may have. If the pot does not have drainage holes, you should use other materials that ensure that the soil does not become waterlogged, such as expanded clay, for example.
Soil is one of the fundamental elements for plant health and there are soils with specific nutrients for certain types of plants, so when it comes to moving your plant to another pot, make sure you choose the most suitable substrate for it.
Finally, it is also very important to prepare the plant for the transplantation process. This process always causes some stress to the plants, so good hydration in the days before transplantation will ensure that your plant withstands this process with fewer complications.
How to transplant the plant
The transplanting process is actually the simplest part that requires the least care, however, there are some tips you should follow so that this moment is not a stressful time for your plant.
The first step is to remove the plant from the pot it is in. Be careful not to damage the roots. Then, in the new pot, cover the bottom with a small amount of the appropriate substrate for your plant.
In the next step, you should place the plant in the new pot and cover it with more substrate so that the pot is well filled and the plant is snug. Then, to secure the plant so that it doesn't move, you should press the soil firmly around the plant. This will ensure that your plant is secure and snug.
Finally, you must water your plant after the entire process and that's it. 
Post-transplant care
After transplanting, there are still some precautions you should take to ensure that your plant goes through the entire process calmly and without stress, so that it can then grow healthy and lush. The place where you place your plant after transplanting is very important. In the following days, the plant should not be exposed to direct sunlight, so you should choose a suitable location away from direct sunlight.
Watering is still essential, however, you must be careful not to soak the soil.
Regarding fertilization, although it is a very important care for the health and longevity of the plants, you should avoid doing it for at least fifteen days after transplanting.
Finally, it is worth mentioning that observation is one of the fundamental steps to keeping your plants healthy. All plants give signs when they are not well, for whatever reason, and it is up to you to take care of them regularly and carefully to ensure that they are well and, in this case, that they are adapting well to their new home. 
Simple, right? Now choose your favorite pots, the best substrates and get to work!
