As Collin Moshman say, it depends on a lot of factors. Rather than trying to define, that "this is my early phase strategy" or "this is my bubble strategy", it is better to understand, what it actually is, that makes tournaments different from cash games and warrent adjustments. And basically its stack sizes and ICM pressure.
Stack sizes matter, because if there is less stack behind, then factors like implied
odds and position will matter less. This mean, that with some sort of middling stack a baby pair often has to be folded, whereas with shallow stacks they can be jammed, and with deep stacks they can be called and played as a setmine.
It also matter, how the table play though. If the table play tight, maybe you can still steal the blinds with a hand like 44 from early position, even your stack is short, because you have a lot of fold
equity, and your cards almost dont even matter. But if most EP opens pick up 3 callers, then you dont want to be in that spot with a hand, that needs to check-fold 88% of the time, if you then just burned up 10% of your stack.
As for ICM pressure it is basically the fact, that chips won are worth less than chips lost. But how large that ICM pressure is, will depend on a lot of things. If you are on the bubble, and someone has 2BB left, then its obviously very bad to go broke before that player, so ICM-pressure is higher than, if the shortest stack is 14BB.
Some bubbles are also more important than others. If you are playing a 9 man SnG, then winning the tournament will only pay 2,5 times as much as min-cashing, whereas in a 180 man SnG on Stars winning pays more than 40 times as much as min-cashing. For this reason there is much more ICM-pressure on the bubble of a 9-man than a 180-man, and it makes no sense to talk about a "bubble strategy", which cover both situations.
In fact in the 180 man you might actually want to ramp up your aggression near the bubble to take advantage of players, who are overly concerned with getting a fairly meaningless min-cash, and who might actually be to easy to push around.