Playing with the lead

[Reel Deal]

Last three MTTs I've played I've found myself with the chiplead roughly near the mid-point of the tournament (one was about a 200+ tourney the other two were smaller WSOP satties with only about 50 players). Each time I seem to find myself becoming a bit too aggressive and running into hands that cause me trouble. On the one hand I know there is value in bullying around your table with a big stack but, on the other hand, does it sometimes make more sense to tighten up and conserve your stack until you get closer to the FT? I'm sure there's a balance in there that works best but I'm really interested in hearing what the successful MTT players here have to say about playing with the lead.

Thanks,

RD