Judo practice is hard, and, no matter what, you will be sweating. A gi absorbs that sweat during the practice, but after practice is over, if you don’t wash your gi, it will start to smell and stains may appear.
A sweaty gi will present a problem for you and for your practice partners. Therefore, it’s recommended that you wash your gi after every practice.
And, this is where a question arises. How many gi’s do you need to own? If you practice almost every day, one gi is not going to cut it. There is simply no time to wash it and for it to dry up before going to practice.
Competitors own a couple of gis in both white and blue colors, and when one gi is drying, they have another one that is ready for use.
Whether you are a competitor or not, owning at least two-three gi’s is highly recommended.