It depends on what you consider "marginal" hands. If you are talking about K10os, KJos, QJos, Q10os, ect... I generally try to stay away from those kind of hands early. If you are talking about 67s, 89s, 56s, ect.. I generally try to stay away from those kind of hands early also. There is nothing worse than splashing around too much and losing some chips then winning less when you do get a strong hand.
As a tournament progresses, the blinds and the antes grow, people naturally tend to tighten up. Hands like 67s, 89s, 56s, can become very profitable for 3 reasons. 1st, people are tighter because a 3x raise is a larger portion of their stack and they are less willing to risk chips on these kind of hands. This allows you to raise these hands as well as call raises because it is much easier to put people on hands. 2nd, you can easily figure out where you are at and its much easier to draw. 3rd, with higher blinds and antes I am more likely to have the
odds to get into hands with marginal cards.
Generally, I'm not playing marginal hands unless I'm pretty confident that I have live cards. I'm going to be especially looking at the
pot odds, types of players at the table, and my position at the table.