With all but the most powerful of hands, you always can justify just calling, rather than raising, when you're in a blind. Remember that you will be in poor position throughout future rounds of betting (except if you're the big blind against only the small blind). If you’re in the small blind against the big blind heads-up, raising is usually correct. But even then, you won’t sacrifice much by just calling.
This poor position on future betting rounds means you have less of an advantage than it may seem. And that makes a raise questionable.
Forced
Also, when you're in a blind, it costs you less voluntary money to call than it costs other players. Remember, you already have entered a significant portion of the bet. You were forced into doing it by the rules.
This means you're often getting a good deal to call, based on pot odds (the amount in the pot versus the amount it costs to call). But when you raise, the proportion of the money you've already blinded becomes less significant, and your pot odds diminish.
For instance, in a limit game, suppose a late position player is the only one to raise your $10 blind to $20. The $5 small blind folds. Now, if you call the $10 raise, you’ll be pursuing the $35 already in the pot (the raiser’s $20, the small blind’s $5, and your $10 big blind).
At this stage of betting, you’re getting $35 to $10 to call, which is 7-to-2 pot odds. But if you reraise and the opponent just calls, you will have risked an additional $20 in pursuit of $45. That’s only 2.25 to 1 (or 4.5 to 2).
Be cautious
It’s important to realize that there are many hands that could make money at 7-to-2 odds (the same as 3.5 to 1), but not at the reduced (2.25 to 1). So, you should be cautious of deliberately reducing your own pot odds to the extent that a hand becomes unprofitable. You should also be concerned that, even if the hand is still profitable after you raise, you might average less profit.
So, if you’re in a blind position, remember this. Whether the game is limit or no-limit, it's hard to justify reducing pot odds with marginally strong hands when you'll have poor position on future betting rounds.
Although you can make exceptions when you’re trying to establish or maintain a dominant image, you should usually stick to this blind-position advice: When in doubt, just calling is safer and often more profitable. Do that. — MC
I notice that the worst mistakes are usually made from the blinds. Many players simply do not understand the math involved and others defend their blinds so vigorously that they dump a bunch of money each round. As usual, Mike makes some very valid points.