What's the best gi?
There really isn't an answer to this question. Obviously, “you get what you pay for” is very true here, but for the top tier of brands there isn't one that's head and shoulders better than the rest. For everyone that loves a brand there's somebody that hates them. The cut, sizing, thickness of lapel, etc. of each gi is different, what works for one person might not work for another.
What's the difference between a BJJ gi and a judo gi?
BJJ gis typically have a slimmer cut. Judo gis are looser to make it easier to grab the label or the sleeve, something that you don't want in BJJ. It's more common for a Judo gi to be two piece than a BJJ gi.
Can I use my Judo gi in BJJ class? Can I use my BJJ gi in Judo class?
This completely depends on your instructor.
Can I use my Judo gi in a BJJ tournament? Can I use my BJJ gi in Judo tournament?
This depends on the tournament. Some tournaments are very strict about what kind of gi you can wear, others aren't. In general, you probably aren't going to have much like trying to get into a Judo tournament with a BJJ gi. Conversely, most BJJ players will gladly take advantage of the cut of your Judo gi in a BJJ tournament.
What's the difference between weaves?
Durability, texture, and weight. A single weave gi will typically last a year or two of regular use, gold/platinum/hybrid weaves last two to three years of regular use, and a double weave gi will last basically forever. Double weaves are known for being very rough, other weaves are softer and smoother. Summer weaves are the lightest and breath the most, as the weave becomes fancier it becomes heavier and breaths less.
Where can I find a <insert color> gi?
White and blue are standard colors for BJJ gis, most gi manufacturers produce gis in both these colors. Red and black are gaining popularity as well. If you are looking for something more exotic like yellow, purple, green, etc you should look into Koral/Vulkan. There are a number of Japanese companies that make non-standard colors but these gis are nearly impossible to purchase outside of Japan at the moment.
What color gi should I get?
Some BJJ schools have rules about what color gis you are allowed to wear, so first, check with your instructor. If your instructor doesn't care, get whatever color you want. A lot of people new to BJJ are concerned that if they come to class wearing a fancy gi they'll be made fun of. If you are concerned about this, then go for a standard color. If you aren't, then who cares? Keep in mind, at tournaments most people sport white and blue, if you don't want to stick out stay with the standard.
Can I dye my gi?
Sure, but you aren't going to get good results. If you're attempting to do this don't use RIT or similarly cheap and crappy grocery store dyes. You need a “fiber reactive” dye. Your best bet is to check out some art stores (even some arts and craft stores have this type of dye) if you want to buy it locally. Dharmatrading.com has a good walkthrough
here. The big problem with dying a gi is the fact that the material is so thick. Dying a tshirt is easy because the fabric is completely saturated the second you put it in the tub, but a gi won't saturate nearly as fast and you'll end up with splotchy weirdness that isn't going to be pretty.
How should I wash my gi?
However the manufacturer tells you to! Typically, it's best to wash your gi in cold water (by hand or in a machine) and air dry it. It takes a long time for a gi to dry, so don't be afraid to toss it in a dryer if you need to, just make sure it's on the lowest setting.
What's up with washing my gi in vinegar?
Some dyed gis aren't “mercerized” (the correct term) or “mercinized.” (a term that people use, but isn't actually what it's called) Basically, that means the gis haven't been treated to lock the dye into the fabric. Gis that haven't had the dye fixed typically let you know that you need to do this. If you buy a gi that asks you to do this, please do it.
How do I shrink a gi?
Wash it with hot water and dry it on a setting higher than the lowest setting. All gis, even pre-shrunk ones, will shrink a bit the first time (sometimes the first couple times) you wash them. Some shrink a very small amount, others will shrink a lot.
How do I fix a stained gi?
In general, you should refrain from bleaching your gi, as it weakens the fabric. Oxyclean, Shout, and other such products are pretty good at treating stains.
What size gi should I get?
Find a size chart! There is no industry-wide standard for gi sizing. Every company is different. Sometimes different products made by the same company will be slightly different. Some companies size charts account for shrinkage, some don't. If you're unsure, email or call the manufacturer, but even that isn't a sure thing.