I mostly use around 1-1.5 paragraphs when roleplaying. I like to use detail and stuff, but not too much. I tend to use simple terms most of the time, but if I get caught up in a big roleplay, I crank up the vocab a bit.
I don't always roleplay, but when I do
I prefer to keep it under 4 paragraphs. I enjoy interaction between characters more than I do the descriptions of our surroundings, so that does leave much to be typed. Its also much quicker than 10+ paragraphs. I prefer to roleplay 3rd person, and while I try use use proper English, I type rather fast for it to happen 100% of the time.