My thoughts on rebuys, I've done ok in them, but am not a tournament master or anything.
I set an amount on rebuy games and stick with it. If AA-QQ gets cracked twice so be it, I'm done
I figure it like this, I don't want to rebuy 5x with a add on and have to place 6th to break even, but I will rebuy once or twice and make up my mind about the add on, which I will probably decline unless I just rebought once right before the add on was offered. I will rarely take an add on if I'm currently with in 1k or so of average and never take it when ahead unless it is a super cheap online game and a buck to add on. My chips are worth more % wise than most of those muppets anyways, and at half average I don't feel pressure unless the blind structure is horrible, your milage may vary, but a tight squeezer approach during the rebuy period works for me.
If the blind structure is horrible I'm probably not playing the game. I could go put it on black and have a better shot of earning money, than playing an hour of poker roulette followed by a total crapshoot. It would probably be more "fun" too, at least if I get to hiss money plays everytime the dealer tries to take my bill and replace it with a chip.
I get more satisfaction getting to the final table with out a rebuy or add on and it increases the value of my tournament dollar to the other knuckleheads, but don't feel bad about whatever results as long as I stick to my budget and play a good game. Given the structure of most tournaments I view them as "fun" over a money making proposition so I'm playing with the hope of winning and putting in my best effort, but not worrying about anything other than my play. If I win money wonderful, if I don't lose too much but made every play a correct one even better. Thinking about the money screws up my game anyways.