This seems to be a common problem with tri-color jades. The stem will turn brown and woody as it matures. So that is normal. The leaves, however, seem to be prone to those brown spots. They don't damage the plant, but are unsightly to those of us who would like to have perfect plants.

I started this thread concerning the spots. My problem turned out to be edema from too much rain and humidity. Others who posted on this thread did not have the same weather that I do and some had their plants indoors. Maybe this thread will give you some insight to the issue.

http://forums.gardenweb.com/discussions/3509597/those-darn-brown-spots-on-jades?n=14

Please ask more questions if this doesn't help!

I have read plants turn brown when too wet, which I thought to be my problem, since I gave them a good misting every day. So I stopped, and it seems as if the spots don't turn worse... I wondered if they have a disease or something. Thanks for the info... It'll lessen my concern :)

Good you stop misting - succulents don't need to be misted, and definitely not every day.