Sunny has done Judo for about 20 years now (since 2000), and washing the Judo Gi is pretty much a daily habit. If done correctly, you might get about 3-6years (Double Weave Judo Gi) and 2-3years (Single Weave Judo Gi) of wear.
It is often recommended to cold wash the Judo Gi for the first wash. Generally, a hot wash would cause the Judo Gi to shrink slightly more than a cold wash. If you know what lengths the arm needs to be at, and the jacket could use a little bit more shrinkage, use the hot wash option,
Set the spin cycle to 400-600. Setting the spin cycle too high might damage the Judo uniform. 400-600 seems to be at a happy medium.
Do not overload the washing machine with clothes or detergent.
I always try to aim for the washing machine to be about 3/4 full. My washing machine is a front loader which holds about a 7kg worht of washing.
Do not mix a white Judo gi with coloured clothing if you're not sure if the clothing will bleed, we too have learnt that the hard way