This is a discussion on How far in the tournament, Rebuy still looks a good choice? within the online poker forums, in the Tournament Poker section; How far in the tournament, Rebuy still looks a good choice?
I'm never rebuying unless I have 30 bigs or more. Unless it's a rare circumstance then I may go to 25BB if the table is weak or the prize pool is lucrative and I'm willing to take the risk. I see some players rebuy all the way to the registration ends with 5-10 BB and punt off tons of buy ins. Waste of money unless you get extremely lucky.
If you're confident in shove/folding correctly you can buy in very late with the intention of hitting a quick couple of double up's but you're gonna need a lot of luck to build a big enough stack to compete to the end game.