when to use up/downstrokes

Hey

When you read a tab, or written music, how can you tell when to use an upstroke or a downstroke for the chords? For example, when i strum how so you know if your meant to be using all downstrokes or all upstrokes? Or if i'm meant to use a mix of both upstrokes and downstrokes, how do i tell when to use a downstroke or upstroke? Is there something written in the music notation that is susposed to tell me?

Or am i susposed to figure that out myself? If i am then how do i figure out if the note is an upstroke or downstroke?

http://guitartricks.com/helptab.php#q4

The above is the GuitarTricks symbol guide for tablature. Not all tablature is written the same; some is very detailed, others are not. Some use different symbols. Usualy it's going to look something like the ones on this page. Or at least a little v pointing down for downstrokes, and a little ^ pointing up for upstrokes.

When it is not indicated then it's really a matter of timing and rhythm. A combination of up and down is common for a lot of styles.

The best advice I can give you when wondering what to use when is to be as lazy as possible :)

By that I mean look at minimizing unecessary movement. If you end up on a downstroke, is it faster and easier to start again using an upstroke or is your last note long enough so you can easily got back to a downstroke.

Some styles use upstrokes a lot because of the difference in the sound it gives to the chord. They are the same notes but since you play them from higher to lower (upstroke) it sounds differently.