Just picked up a new deck thats 8.3 to learn some small street tricks on and board slides to get ready for snowboarding.  but now that i'm looking around i see a lot of people are using narrow decks for street.  before i buy new trucks should i think if going to a 7.0-7.5?  i've noticed noone really carries wider boards or trucks.

i ride a 8.5
its really what you plan on doing with it
size of a deck is for faster tricks and easier to control
if you have a huge board (8.0-8.5) you will need to put more power behide it to do stuff
if you get a smaller deck (7.0-7.5) there are less space to put your feet but board will be lighter and more easier to flip
where did you buy it
some shops have samples to stand on before buying
but its really up to yourself

I've noticed the board I'm riding is a bit harder to ride street with compared to boards of other skaters that ive tried bc its much wider. I think i'm going to get a new deck under 7.5 bc there arent any mini ramps around. 

don't go smaller than a 7.5
i find anything under that is to small unless your under 10

Yeah I started on a wide deck with wide trucks and eventually scaled down.  Now I ride a 7.5 deck and ride mostly street

yeah alot of people do it that way because there is more board to land on
i just got my oldschool deck its a 9.0