I would almost always play them, unless someone made a verry substantial
bet. The reason for this is that you could make a lot of money with a suited
connector. A lot of people dont expect them, especially if they are low
cards. Imagine someone raises with ace king, and you call with 4 5 suited.
A 2 3 comes... you have him in your pocket... or even 2 3 6, he would raise
thinking you didnt catch anything since the board was so slow... hell you
dont even need to catch on the flop, a outside straight is good enough.
In early position I usually just call, since I dont know what the other people
have so by raising I might get a reraise and the pot would be too big for
my taist. In late position however sometimes you might want to raise just
so that people put you on a totally different hand. So if you catch they'll
think your
bluffing, and if you miss, you can make a good
bluff, especially
if the cards are high on the board since they will think you raised preflop
with high cards....